Various improvements to tab panels (#3315)

* 'Native' Bootstrap 4 tabset panel support * downgrade error to warning; improve the messaging * Make tab anchor selectors more a bit more sensible and consistent across versions * More of the same * fix silly bug * Be more careful about unpacking a .nav-item into a .dropdown-item * Keep refactoring R logic to make it cleaner and easier to reuse elsewhere * Go back to the purely class based CSS selectors for BS4 tab input * Keep supporting off-label behavior of shiny.tag getting transformed into 'empty' nav/tab * Add header and footer args to tabsetPanel()/navlistPanel() since there is precedence in navbarPage() and mention them in the warning * Drop NULLs instead of creating an empty nav from them, closes #1928 * Remove tabPanelMenu() alias * Add a card argument for wrapping content in a card * Throw an error if card=T is used outside of a BS4+ context * No more tabPanelMenu() alias * Document (GitHub Actions) * Port JS changes to TypeScript * Allow liTag to be assigned a new value * abort() is no longer being used * Add some unit tests * Document the new card argument * Get tests passing on older R versions * Get tests passing on older R versions * Get tests passing on older R versions * Skip snapshots on R < 3.6 * require dev version of htmltools * remove card argument (at least for now) * Document (GitHub Actions) * Update tests/testthat/test-tabPanel.R Co-authored-by: Winston Chang <winston@stdout.org> * Have processDeps() call renderTags() on tagFunction() objects Co-authored-by: cpsievert <cpsievert@users.noreply.github.com> Co-authored-by: Winston Chang <winston@stdout.org>
2026-01-10 07:28:01 -05:00 · 2021-03-22 12:37:57 -05:00
parent d582e53f73
commit 32d0e146ad
14 changed files with 847 additions and 216 deletions
--- a/1
+++ b/1
@@ -408,6 +408,7 @@ importFrom(rlang,is_false)
 importFrom(rlang,is_missing)
 importFrom(rlang,is_na)
 importFrom(rlang,is_quosure)
+importFrom(rlang,list2)
 importFrom(rlang,maybe_missing)
 importFrom(rlang,missing_arg)
 importFrom(rlang,new_function)
--- a/R/bootstrap.R
+++ b/R/bootstrap.R
@@ -163,6 +163,15 @@ getCurrentTheme <- function() {
  getShinyOption("bootstrapTheme", default = NULL)
 }

+getCurrentVersion <- function() {
+  theme <- getCurrentTheme()
+  if (bslib::is_bs_theme(theme)) {
+    bslib::theme_version(theme)
+  } else {
+    strsplit(bootstrapVersion, ".", fixed = TRUE)[[1]][[1]]
+  }
+}
+
 setCurrentTheme <- function(theme) {
  shinyOptions(bootstrapTheme = theme)
 }
@@ -211,7 +220,7 @@ registerThemeDependency <- function(func) {

 bootstrapDependency <- function(theme) {
  htmlDependency(
-    "bootstrap", "3.4.1",
+    "bootstrap", bootstrapVersion,
    c(
      href = "shared/bootstrap",
      file = system.file("www/shared/bootstrap", package = "shiny")
@@ -230,6 +239,8 @@ bootstrapDependency <- function(theme) {
  )
 }

+bootstrapVersion <- "3.4.1"
+

 #' @rdname bootstrapPage
 #' @export
@@ -436,10 +447,11 @@ navbarPage <- function(title,
  pageTitle <- title

  # navbar class based on options
+  # TODO: tagFunction() the navbar logic?
  navbarClass <- "navbar navbar-default"
  position <- match.arg(position)
  if (!is.null(position))
-    navbarClass <- paste(navbarClass, " navbar-", position, sep = "")
+    navbarClass <- paste0(navbarClass, " navbar-", position)
  if (inverse)
    navbarClass <- paste(navbarClass, "navbar-inverse")

@@ -447,21 +459,14 @@ navbarPage <- function(title,
    selected <- restoreInput(id = id, default = selected)

  # build the tabset
-  tabs <- list(...)
-  tabset <- buildTabset(tabs, "nav navbar-nav", NULL, id, selected)
+  tabset <- buildTabset(..., ulClass = "nav navbar-nav", id = id, selected = selected)

-  # function to return plain or fluid class name
-  className <- function(name) {
-    if (fluid)
-      paste(name, "-fluid", sep="")
-    else
-      name
-  }
+  containerClass <- paste0("container", if (fluid) "-fluid")

  # built the container div dynamically to support optional collapsibility
  if (collapsible) {
-    navId <- paste("navbar-collapse-", p_randomInt(1000, 10000), sep="")
-    containerDiv <- div(class=className("container"),
+    navId <- paste0("navbar-collapse-", p_randomInt(1000, 10000))
+    containerDiv <- div(class=containerClass,
      div(class="navbar-header",
        tags$button(type="button", class="navbar-toggle collapsed",
          `data-toggle`="collapse", `data-target`=paste0("#", navId),
@@ -475,7 +480,7 @@ navbarPage <- function(title,
      div(class="navbar-collapse collapse", id=navId, tabset$navList)
    )
  } else {
-    containerDiv <- div(class=className("container"),
+    containerDiv <- div(class=containerClass,
      div(class="navbar-header",
        span(class="navbar-brand", pageTitle)
      ),
@@ -484,7 +489,7 @@ navbarPage <- function(title,
  }

  # build the main tab content div
-  contentDiv <- div(class=className("container"))
+  contentDiv <- div(class=containerClass)
  if (!is.null(header))
    contentDiv <- tagAppendChild(contentDiv, div(class="row", header))
  contentDiv <- tagAppendChild(contentDiv, tabset$content)
@@ -511,11 +516,15 @@ navbarPage <- function(title,
 navbarMenu <- function(title, ..., menuName = title, icon = NULL) {
  structure(list(title = title,
                 menuName = menuName,
-                 tabs = list(...),
+                 tabs = list2(...),
                 iconClass = iconClass(icon)),
            class = "shiny.navbarmenu")
 }

+isNavbarMenu <- function(x) {
+  inherits(x, "shiny.navbarmenu")
+}
+
 #' Create a well panel
 #'
 #' Creates a panel with a slightly inset border and grey background. Equivalent
@@ -656,6 +665,13 @@ tabPanel <- function(title, ..., value = title, icon = NULL) {
    ...
  )
 }
+
+isTabPanel <- function(x) {
+  if (!inherits(x, "shiny.tag")) return(FALSE)
+  class <- tagGetAttribute(x, "class") %||% ""
+  "tab-pane" %in% strsplit(class, "\\s+")[[1]]
+}
+
 #' @export
 #' @describeIn tabPanel Create a tab panel that drops the title argument.
 #'   This function should be used within `tabsetPanel(type = "hidden")`. See [tabsetPanel()] for example usage.
@@ -693,6 +709,7 @@ tabPanelBody <- function(value, ..., icon = NULL) {
 #' }
 #' @param position This argument is deprecated; it has been discontinued in
 #'   Bootstrap 3.
+#' @inheritParams navbarPage
 #' @return A tabset that can be passed to [mainPanel()]
 #'
 #' @seealso [tabPanel()], [updateTabsetPanel()],
@@ -742,6 +759,8 @@ tabsetPanel <- function(...,
                        id = NULL,
                        selected = NULL,
                        type = c("tabs", "pills", "hidden"),
+                        header = NULL,
+                        footer = NULL,
                        position = deprecated()) {
  if (lifecycle::is_present(position)) {
    shinyDeprecated(
@@ -753,18 +772,18 @@ tabsetPanel <- function(...,
  if (!is.null(id))
    selected <- restoreInput(id = id, default = selected)

-  # build the tabset
-  tabs <- list(...)
  type <- match.arg(type)
+  tabset <- buildTabset(..., ulClass = paste0("nav nav-", type), id = id, selected = selected)

-  tabset <- buildTabset(tabs, paste0("nav nav-", type), NULL, id, selected)
-
-  # create the content
-  first <- tabset$navList
-  second <- tabset$content
-
-  # create the tab div
-  tags$div(class = "tabbable", first, second)
+  tags$div(
+    class = "tabbable",
+    !!!dropNulls(list(
+      tabset$navList,
+      header,
+      tabset$content,
+      footer
+    ))
+  )
 }

 #' Create a navigation list panel
@@ -784,8 +803,10 @@ tabsetPanel <- function(...,
 #'   navigation list.
 #' @param fluid `TRUE` to use fluid layout; `FALSE` to use fixed
 #'   layout.
-#' @param widths Column withs of the navigation list and tabset content areas
+#' @param widths Column widths of the navigation list and tabset content areas
 #'   respectively.
+#' @inheritParams tabsetPanel
+#' @inheritParams navbarPage
 #'
 #' @details You can include headers within the `navlistPanel` by including
 #'   plain text elements in the list. Versions of Shiny before 0.11 supported
@@ -812,37 +833,30 @@ tabsetPanel <- function(...,
 navlistPanel <- function(...,
                         id = NULL,
                         selected = NULL,
+                         header = NULL,
+                         footer = NULL,
                         well = TRUE,
                         fluid = TRUE,
                         widths = c(4, 8)) {

-  # text filter for headers
-  textFilter <- function(text) {
-      tags$li(class="navbar-brand", text)
-  }
-
  if (!is.null(id))
    selected <- restoreInput(id = id, default = selected)

-  # build the tabset
-  tabs <- list(...)
-  tabset <- buildTabset(tabs,
-                        "nav nav-pills nav-stacked",
-                        textFilter,
-                        id,
-                        selected)
-
-  # create the columns
-  columns <- list(
-    column(widths[[1]], class=ifelse(well, "well", ""), tabset$navList),
-    column(widths[[2]], tabset$content)
+  tabset <- buildTabset(
+    ..., ulClass = "nav nav-pills nav-stacked",
+    textFilter = function(text) tags$li(class = "navbar-brand", text),
+    id = id, selected = selected
  )

-  # return the row
-  if (fluid)
-    fluidRow(columns)
-  else
-    fixedRow(columns)
+  row <- if (fluid) fluidRow else fixedRow
+
+  row(
+    column(widths[[1]], class = if (well) "well", tabset$navList),
+    column(
+      widths[[2]],
+      !!!dropNulls(list(header, tabset$content, footer))
+    )
+  )
 }

 # Helpers to build tabsetPanels (& Co.) and their elements
@@ -860,14 +874,14 @@ containsSelectedTab <- function(tabs) {
 }

 findAndMarkSelectedTab <- function(tabs, selected, foundSelected) {
-  tabs <- lapply(tabs, function(div) {
-    if (foundSelected || is.character(div)) {
+  tabs <- lapply(tabs, function(x) {
+    if (foundSelected || is.character(x)) {
      # Strings are not selectable items

-    } else if (inherits(div, "shiny.navbarmenu")) {
+    } else if (isNavbarMenu(x)) {
      # Recur for navbarMenus
-      res <- findAndMarkSelectedTab(div$tabs, selected, foundSelected)
-      div$tabs <- res$tabs
+      res <- findAndMarkSelectedTab(x$tabs, selected, foundSelected)
+      x$tabs <- res$tabs
      foundSelected <<- res$foundSelected

    } else {
@@ -876,16 +890,16 @@ findAndMarkSelectedTab <- function(tabs, selected, foundSelected) {
      # mark first available item as selected
      if (is.null(selected)) {
        foundSelected <<- TRUE
-        div <- markTabAsSelected(div)
+        x <- markTabAsSelected(x)
      } else {
-        tabValue <- div$attribs$`data-value` %||% div$attribs$title
+        tabValue <- x$attribs$`data-value` %||% x$attribs$title
        if (identical(selected, tabValue)) {
          foundSelected <<- TRUE
-          div <- markTabAsSelected(div)
+          x <- markTabAsSelected(x)
        }
      }
    }
-    return(div)
+    return(x)
  })
  return(list(tabs = tabs, foundSelected = foundSelected))
 }
@@ -911,9 +925,10 @@ navbarMenuTextFilter <- function(text) {

 # This function is called internally by navbarPage, tabsetPanel
 # and navlistPanel
-buildTabset <- function(tabs, ulClass, textFilter = NULL, id = NULL,
+buildTabset <- function(..., ulClass, textFilter = NULL, id = NULL,
                        selected = NULL, foundSelected = FALSE) {

+  tabs <- dropNulls(list2(...))
  res <- findAndMarkSelectedTab(tabs, selected, foundSelected)
  tabs <- res$tabs
  foundSelected <- res$foundSelected
@@ -934,10 +949,10 @@ buildTabset <- function(tabs, ulClass, textFilter = NULL, id = NULL,
            tabs = tabs, textFilter = textFilter)

  tabNavList <- tags$ul(class = ulClass, id = id,
-                  `data-tabsetid` = tabsetId, lapply(tabs, "[[", 1))
+                  `data-tabsetid` = tabsetId, !!!lapply(tabs, "[[", "liTag"))

  tabContent <- tags$div(class = "tab-content",
-                  `data-tabsetid` = tabsetId, lapply(tabs, "[[", 2))
+                  `data-tabsetid` = tabsetId, !!!lapply(tabs, "[[", "divTag"))

  list(navList = tabNavList, content = tabContent)
 }
@@ -949,56 +964,173 @@ buildTabset <- function(tabs, ulClass, textFilter = NULL, id = NULL,
 buildTabItem <- function(index, tabsetId, foundSelected, tabs = NULL,
                         divTag = NULL, textFilter = NULL) {

-  divTag <- if (!is.null(divTag)) divTag else tabs[[index]]
+  divTag <- divTag %||% tabs[[index]]

+  # Handles navlistPanel() headers and dropdown dividers
  if (is.character(divTag) && !is.null(textFilter)) {
-    # text item: pass it to the textFilter if it exists
-    liTag <- textFilter(divTag)
-    divTag <- NULL
-
-  } else if (inherits(divTag, "shiny.navbarmenu")) {
-    # navbarMenu item: build the child tabset
-    tabset <- buildTabset(divTag$tabs, "dropdown-menu",
-      navbarMenuTextFilter, foundSelected = foundSelected)
-
-    # if this navbarMenu contains a selected item, mark it active
-    containsSelected <- containsSelectedTab(divTag$tabs)
-    liTag <- tags$li(
-      class = paste0("dropdown", if (containsSelected) " active"),
-      tags$a(href = "#",
-        class = "dropdown-toggle", `data-toggle` = "dropdown",
-        `data-value` = divTag$menuName,
-        getIcon(iconClass = divTag$iconClass),
-        divTag$title, tags$b(class = "caret")
-      ),
-      tabset$navList   # inner tabPanels items
-    )
-    # list of tab content divs from the child tabset
-    divTag <- tabset$content$children
-
-  } else {
-    # tabPanel item: create the tab's liTag and divTag
-    tabId <- paste("tab", tabsetId, index, sep = "-")
-    liTag <- tags$li(
-               tags$a(
-                 href = paste("#", tabId, sep = ""),
-                 `data-toggle` = "tab",
-                 `data-value` = divTag$attribs$`data-value`,
-                 getIcon(iconClass = divTag$attribs$`data-icon-class`),
-                 divTag$attribs$title
-               )
-    )
-    # if this tabPanel is selected item, mark it active
-    if (isTabSelected(divTag)) {
-      liTag$attribs$class <- "active"
-      divTag$attribs$class <- "tab-pane active"
-    }
-    divTag$attribs$id <- tabId
-    divTag$attribs$title <- NULL
+    return(list(liTag = textFilter(divTag), divTag = NULL))
  }
-  return(list(liTag = liTag, divTag = divTag))
+
+  if (isNavbarMenu(divTag)) {
+    # tabPanelMenu item: build the child tabset
+    tabset <- buildTabset(
+      !!!divTag$tabs, ulClass = "dropdown-menu",
+      textFilter = navbarMenuTextFilter,
+      foundSelected = foundSelected
+    )
+    return(buildDropdown(divTag, tabset))
+  }
+
+  if (isTabPanel(divTag)) {
+    return(buildNavItem(divTag, tabsetId, index))
+  }
+
+  # The behavior is undefined at this point, so construct a condition message
+  msg <- paste0(
+    "Expected a collection `tabPanel()`s",
+    if (is.null(textFilter)) " and `navbarMenu()`.",
+    if (!is.null(textFilter)) ", `navbarMenu()`, and/or character strings.",
+    " Consider using `header` or `footer` if you wish to place content above (or below) every panel's contents"
+  )
+
+  # Luckily this case has never worked, so it's safe to throw here
+  # https://github.com/rstudio/shiny/issues/3313
+  if (!inherits(divTag, "shiny.tag"))  {
+    stop(msg, call. = FALSE)
+  }
+
+  # Unfortunately, this 'off-label' use case creates an 'empty' nav and includes
+  # the divTag content on every tab. There shouldn't be any reason to be relying on
+  # this behavior since we now have pre/post arguments, so throw a warning, but still
+  # support the use case since we don't make breaking changes
+  warning(msg, call. = FALSE)
+
+  return(buildNavItem(divTag, tabsetId, index))
 }

+buildNavItem <- function(divTag, tabsetId, index) {
+  id <- paste("tab", tabsetId, index, sep = "-")
+  title <- tagGetAttribute(divTag, "title")
+  value <- tagGetAttribute(divTag, "data-value")
+  icon <- getIcon(iconClass = tagGetAttribute(divTag, "data-icon-class"))
+  active <- isTabSelected(divTag)
+  divTag <- tagAppendAttributes(divTag, class = if (active) "active")
+  divTag$attribs$id <- id
+  divTag$attribs$title <- NULL
+  list(
+    divTag = divTag,
+    liTag = tagFunction(function() {
+      navItem <- if ("3" %in% getCurrentVersion()) bs3NavItem else bs4NavItem
+      navItem(id, title, value, icon, active)
+    })
+  )
+}
+
+buildDropdown <- function(divTag, tabset) {
+  title <- divTag$title
+  value <- divTag$menuName
+  icon <- getIcon(iconClass = divTag$iconClass)
+  active <- containsSelectedTab(divTag$tabs)
+  list(
+    # list of tab content divs from the child tabset
+    divTag = tabset$content$children,
+    liTag = tagFunction(function() {
+      if ("3" %in% getCurrentVersion()) {
+        bs3NavItemDropdown(title, value, icon, active, tabset$navList)
+      } else {
+        # In BS4, dropdown nav anchors can't be wrapped in a <li> tag
+        # and also need .nav-link replaced with .dropdown-item to be
+        # styled sensibly
+        items <- tabset$navList
+        items$children <- lapply(items$children, function(x) {
+          # x should be a tagFunction() due to the else block below
+          x <- if (inherits(x, "shiny.tag.function")) x() else x
+          # Replace <li class="nav-item"><a class="nav-link"></a></li>
+          #    with <a class="dropdown-item"></a>
+          if (tagHasClass(x, "nav-item")) {
+            x <- x$children[[1]]
+            x$attribs$class <- "dropdown-item"
+          }
+          x
+        })
+        bs4NavItemDropdown(title, value, icon, active, items)
+      }
+    })
+  )
+}
+
+
+bs3NavItemDropdown <- function(title, value, icon, active, items) {
+  tags$li(
+    class = "dropdown",
+    class = if (active) "active", # BS3
+    tags$a(
+      href = "#",
+      class = "dropdown-toggle",
+      `data-toggle` = "dropdown",
+      `data-value` = value,
+      icon,
+      title, tags$b(class = "caret")
+    ),
+    items
+  )
+}
+
+bs3NavItem <- function(id, title, value, icon, active) {
+  tags$li(
+    class = if (active) "active",
+    tags$a(
+      href = paste0("#", id),
+      `data-toggle` = "tab",
+      `data-value` = value,
+      icon,
+      title
+    )
+  )
+}
+
+bs4NavItemDropdown <- function(title, value, icon, active, items) {
+  tags$li(
+    class = "dropdown",
+    class = "nav-item",
+    tags$a(
+      href = "#",
+      class = "dropdown-toggle",
+      class = "nav-link",
+      class = if (active) "active",
+      `data-toggle` = "dropdown",
+      `data-value` = value,
+      icon,
+      title,
+      tags$b(class = "caret") # TODO: can be removed?
+    ),
+    items
+  )
+}
+
+bs4NavItem <- function(id, title, value, icon, active) {
+  tags$li(
+    class = "nav-item",
+    tags$a(
+      class = "nav-link",
+      class = if (active) "active",
+      href = paste0("#", id),
+      `data-toggle` = "tab",
+      `data-value` = value,
+      icon,
+      title
+    )
+  )
+}
+
+# TODO: something like this should exist in htmltools
+tagHasClass <- function(x, class) {
+  if (!inherits(x, "shiny.tag")) return(FALSE)
+  classes <- unlist(x$attribs[names(x$attribs) %in% "class"], use.names = FALSE)
+  if (!length(classes)) return(FALSE)
+  classes <- unlist(strsplit(classes, split = "\\s+"), use.names = FALSE)
+  isTRUE(class %in% classes)
+}

 #' Create a text output element
 #'
--- a/R/html-deps.R
+++ b/R/html-deps.R
@@ -49,6 +49,12 @@ processDeps <- function(tags, session) {
  )
  names(dependencies) <- NULL

+  # If ui is a tagFunction() (e.g., insertTab() et al),
+  # then doRenderTags() won't work...
+  if (inherits(ui, "shiny.tag.function")) {
+    ui <- renderTags(ui)$html
+  }
+
  list(
    html = doRenderTags(ui),
    deps = dependencies
--- a/R/shiny-package.R
+++ b/R/shiny-package.R
@@ -14,7 +14,7 @@
 #'    quo enquo as_function get_expr get_env new_function enquos
 #'    eval_tidy expr pairlist2 new_quosure enexpr as_quosure is_quosure inject
 #'    enquos0 zap_srcref %||% is_na
-#'    is_false
+#'    is_false list2
 #'    missing_arg is_missing maybe_missing
 #' @importFrom ellipsis
 #'    check_dots_empty check_dots_unnamed
--- a/inst/www/shared/shiny.js
+++ b/inst/www/shared/shiny.js
@@ -1198,6 +1198,26 @@
    };
  });

+  // node_modules/core-js/internals/regexp-exec-abstract.js
+  var require_regexp_exec_abstract = __commonJS(function(exports2, module2) {
+    var classof2 = require_classof_raw();
+    var regexpExec2 = require_regexp_exec();
+    module2.exports = function(R, S) {
+      var exec = R.exec;
+      if (typeof exec === "function") {
+        var result = exec.call(R, S);
+        if (typeof result !== "object") {
+          throw TypeError("RegExp exec method returned something other than an Object or null");
+        }
+        return result;
+      }
+      if (classof2(R) !== "RegExp") {
+        throw TypeError("RegExp#exec called on incompatible receiver");
+      }
+      return regexpExec2.call(R, S);
+    };
+  });
+
  // node_modules/core-js/internals/get-substitution.js
  var require_get_substitution = __commonJS(function(exports2, module2) {
    var toObject4 = require_to_object();
@@ -1246,26 +1266,6 @@
    };
  });

-  // node_modules/core-js/internals/regexp-exec-abstract.js
-  var require_regexp_exec_abstract = __commonJS(function(exports2, module2) {
-    var classof2 = require_classof_raw();
-    var regexpExec2 = require_regexp_exec();
-    module2.exports = function(R, S) {
-      var exec = R.exec;
-      if (typeof exec === "function") {
-        var result = exec.call(R, S);
-        if (typeof result !== "object") {
-          throw TypeError("RegExp exec method returned something other than an Object or null");
-        }
-        return result;
-      }
-      if (classof2(R) !== "RegExp") {
-        throw TypeError("RegExp#exec called on incompatible receiver");
-      }
-      return regexpExec2.call(R, S);
-    };
-  });
-
  // node_modules/core-js/internals/is-regexp.js
  var require_is_regexp = __commonJS(function(exports2, module2) {
    var isObject3 = require_is_object();
@@ -2996,7 +2996,9 @@
        function getTargetTabs($tabset, $tabContent, target) {
          var dataValue = "[data-value='" + $escape(target) + "']";
          var $aTag = $tabset.find("a" + dataValue);
-          var $liTag = $aTag.parent();
+          var $liTag = $aTag.parent("li");
+          if ($liTag.length === 0)
+            $liTag = $aTag;
          if ($liTag.length === 0) {
            throw "There is no tabPanel (or navbarMenu) with value (or menuName) equal to '" + target + "'";
          }
@@ -3005,7 +3007,10 @@
          if ($aTag.attr("data-toggle") === "dropdown") {
            var $dropdownTabset = $aTag.find("+ ul.dropdown-menu");
            var dropdownId = $dropdownTabset.attr("data-tabsetid");
-            var $dropdownLiTags = $dropdownTabset.find("a[data-toggle='tab']").parent("li");
+            var $dropdownLiTags = $dropdownTabset.find("a[data-toggle='tab']");
+            if ($dropdownLiTags.parent("li").length > 0) {
+              $dropdownLiTags = $dropdownLiTags.parent("li");
+            }
            $dropdownLiTags.each(function(i, el) {
              $liTags.push(import_jquery6.default(el));
            });
@@ -3036,6 +3041,9 @@
          if (message.target !== null) {
            target = getTargetTabs($tabset, $tabContent, message.target);
            $targetLiTag = target.$liTag;
+            if ($targetLiTag.hasClass("dropdown-item")) {
+              $liTag = $aTag.removeClass("nav-link").addClass("dropdown-item");
+            }
          }
          var dropdown = getDropdown();
          if (dropdown !== null) {
@@ -3047,7 +3055,10 @@
          if ($aTag.attr("data-toggle") === "tab") {
            var index = getTabIndex($tabset, tabsetId);
            var tabId = "tab-" + tabsetId + "-" + index;
-            $liTag.find("> a").attr("href", "#" + tabId);
+            var anchor = $liTag.find("> a");
+            if (anchor.length === 0)
+              anchor = $liTag;
+            anchor.attr("href", "#" + tabId);
            $divTag.attr("id", tabId);
          }
          if (message.position === "before") {
@@ -3080,8 +3091,8 @@
          }
          function getTabIndex($tabset2, tabsetId2) {
            var existingTabIds = [0];
-            $tabset2.find("> li").each(function() {
-              var $tab = import_jquery6.default(this).find("> a[data-toggle='tab']");
+            $tabset2.find("a[data-toggle='tab']").each(function() {
+              var $tab = import_jquery6.default(this);
              if ($tab.length > 0) {
                var href = $tab.attr("href").replace(/.*(?=#[^\s]+$)/, "");
                var _index = href.replace("#tab-" + tabsetId2 + "-", "");
@@ -6084,7 +6095,7 @@
          return import_jquery6.default(scope).find("ul.nav.shiny-tab-input");
        },
        getValue: function getValue(el) {
-          var anchor = import_jquery6.default(el).find("li:not(.dropdown).active").children("a");
+          var anchor = isBS3() ? import_jquery6.default(el).find("li:not(.dropdown).active > a") : import_jquery6.default(el).find(".nav-link:not(.dropdown-toggle).active, .dropdown-menu > .dropdown-item.active");
          if (anchor.length === 1)
            return this._getTabName(anchor);
          return null;
@@ -6093,7 +6104,7 @@
          var self2 = this;
          var success = false;
          if (value) {
-            var anchors = import_jquery6.default(el).find("li:not(.dropdown)").children("a");
+            var anchors = isBS3() ? import_jquery6.default(el).find("li:not(.dropdown) > a") : import_jquery6.default(el).find(".nav-link:not(.dropdown-toggle), .dropdown-menu > .dropdown-item");
            anchors.each(function() {
              if (self2._getTabName(import_jquery6.default(this)) === value) {
                import_jquery6.default(this).tab("show");
@@ -7259,28 +7270,68 @@
    }, {unsafe: true});
  }

-  // node_modules/core-js/modules/es.string.replace.js
+  // node_modules/core-js/modules/es.string.match.js
  "use strict";
  var fixRegExpWellKnownSymbolLogic = require_fix_regexp_well_known_symbol_logic();
  var anObject2 = require_an_object();
  var toLength4 = require_to_length();
-  var toInteger2 = require_to_integer();
  var requireObjectCoercible = require_require_object_coercible();
  var advanceStringIndex = require_advance_string_index();
-  var getSubstitution = require_get_substitution();
  var regExpExec = require_regexp_exec_abstract();
+  fixRegExpWellKnownSymbolLogic("match", 1, function(MATCH, nativeMatch, maybeCallNative) {
+    return [
+      function match(regexp) {
+        var O = requireObjectCoercible(this);
+        var matcher = regexp == void 0 ? void 0 : regexp[MATCH];
+        return matcher !== void 0 ? matcher.call(regexp, O) : new RegExp(regexp)[MATCH](String(O));
+      },
+      function(regexp) {
+        var res = maybeCallNative(nativeMatch, regexp, this);
+        if (res.done)
+          return res.value;
+        var rx = anObject2(regexp);
+        var S = String(this);
+        if (!rx.global)
+          return regExpExec(rx, S);
+        var fullUnicode = rx.unicode;
+        rx.lastIndex = 0;
+        var A = [];
+        var n = 0;
+        var result;
+        while ((result = regExpExec(rx, S)) !== null) {
+          var matchStr = String(result[0]);
+          A[n] = matchStr;
+          if (matchStr === "")
+            rx.lastIndex = advanceStringIndex(S, toLength4(rx.lastIndex), fullUnicode);
+          n++;
+        }
+        return n === 0 ? null : A;
+      }
+    ];
+  });
+
+  // node_modules/core-js/modules/es.string.replace.js
+  "use strict";
+  var fixRegExpWellKnownSymbolLogic2 = require_fix_regexp_well_known_symbol_logic();
+  var anObject3 = require_an_object();
+  var toLength5 = require_to_length();
+  var toInteger2 = require_to_integer();
+  var requireObjectCoercible2 = require_require_object_coercible();
+  var advanceStringIndex2 = require_advance_string_index();
+  var getSubstitution = require_get_substitution();
+  var regExpExec2 = require_regexp_exec_abstract();
  var max3 = Math.max;
  var min2 = Math.min;
  var maybeToString = function(it) {
    return it === void 0 ? it : String(it);
  };
-  fixRegExpWellKnownSymbolLogic("replace", 2, function(REPLACE, nativeReplace, maybeCallNative, reason) {
+  fixRegExpWellKnownSymbolLogic2("replace", 2, function(REPLACE, nativeReplace, maybeCallNative, reason) {
    var REGEXP_REPLACE_SUBSTITUTES_UNDEFINED_CAPTURE = reason.REGEXP_REPLACE_SUBSTITUTES_UNDEFINED_CAPTURE;
    var REPLACE_KEEPS_$0 = reason.REPLACE_KEEPS_$0;
    var UNSAFE_SUBSTITUTE = REGEXP_REPLACE_SUBSTITUTES_UNDEFINED_CAPTURE ? "$" : "$0";
    return [
      function replace(searchValue, replaceValue) {
-        var O = requireObjectCoercible(this);
+        var O = requireObjectCoercible2(this);
        var replacer = searchValue == void 0 ? void 0 : searchValue[REPLACE];
        return replacer !== void 0 ? replacer.call(searchValue, O, replaceValue) : nativeReplace.call(String(O), searchValue, replaceValue);
      },
@@ -7290,7 +7341,7 @@
          if (res.done)
            return res.value;
        }
-        var rx = anObject2(regexp);
+        var rx = anObject3(regexp);
        var S = String(this);
        var functionalReplace = typeof replaceValue === "function";
        if (!functionalReplace)
@@ -7302,7 +7353,7 @@
        }
        var results = [];
        while (true) {
-          var result = regExpExec(rx, S);
+          var result = regExpExec2(rx, S);
          if (result === null)
            break;
          results.push(result);
@@ -7310,7 +7361,7 @@
            break;
          var matchStr = String(result[0]);
          if (matchStr === "")
-            rx.lastIndex = advanceStringIndex(S, toLength4(rx.lastIndex), fullUnicode);
+            rx.lastIndex = advanceStringIndex2(S, toLength5(rx.lastIndex), fullUnicode);
        }
        var accumulatedResult = "";
        var nextSourcePosition = 0;
@@ -7342,13 +7393,13 @@

  // node_modules/core-js/modules/es.string.split.js
  "use strict";
-  var fixRegExpWellKnownSymbolLogic2 = require_fix_regexp_well_known_symbol_logic();
+  var fixRegExpWellKnownSymbolLogic3 = require_fix_regexp_well_known_symbol_logic();
  var isRegExp = require_is_regexp();
-  var anObject3 = require_an_object();
-  var requireObjectCoercible2 = require_require_object_coercible();
+  var anObject4 = require_an_object();
+  var requireObjectCoercible3 = require_require_object_coercible();
  var speciesConstructor = require_species_constructor();
-  var advanceStringIndex2 = require_advance_string_index();
-  var toLength5 = require_to_length();
+  var advanceStringIndex3 = require_advance_string_index();
+  var toLength6 = require_to_length();
  var callRegExpExec = require_regexp_exec_abstract();
  var regexpExec = require_regexp_exec();
  var fails5 = require_fails();
@@ -7358,11 +7409,11 @@
  var SUPPORTS_Y = !fails5(function() {
    return !RegExp(MAX_UINT32, "y");
  });
-  fixRegExpWellKnownSymbolLogic2("split", 2, function(SPLIT, nativeSplit, maybeCallNative) {
+  fixRegExpWellKnownSymbolLogic3("split", 2, function(SPLIT, nativeSplit, maybeCallNative) {
    var internalSplit;
    if ("abbc".split(/(b)*/)[1] == "c" || "test".split(/(?:)/, -1).length != 4 || "ab".split(/(?:ab)*/).length != 2 || ".".split(/(.?)(.?)/).length != 4 || ".".split(/()()/).length > 1 || "".split(/.?/).length) {
      internalSplit = function(separator, limit) {
-        var string = String(requireObjectCoercible2(this));
+        var string = String(requireObjectCoercible3(this));
        var lim = limit === void 0 ? MAX_UINT32 : limit >>> 0;
        if (lim === 0)
          return [];
@@ -7405,7 +7456,7 @@
      internalSplit = nativeSplit;
    return [
      function split(separator, limit) {
-        var O = requireObjectCoercible2(this);
+        var O = requireObjectCoercible3(this);
        var splitter = separator == void 0 ? void 0 : separator[SPLIT];
        return splitter !== void 0 ? splitter.call(separator, O, limit) : internalSplit.call(String(O), separator, limit);
      },
@@ -7413,7 +7464,7 @@
        var res = maybeCallNative(internalSplit, regexp, this, limit, internalSplit !== nativeSplit);
        if (res.done)
          return res.value;
-        var rx = anObject3(regexp);
+        var rx = anObject4(regexp);
        var S = String(this);
        var C = speciesConstructor(rx, RegExp);
        var unicodeMatching = rx.unicode;
@@ -7431,8 +7482,8 @@
          splitter.lastIndex = SUPPORTS_Y ? q : 0;
          var z = callRegExpExec(splitter, SUPPORTS_Y ? S : S.slice(q));
          var e;
-          if (z === null || (e = min3(toLength5(splitter.lastIndex + (SUPPORTS_Y ? 0 : q)), S.length)) === p) {
-            q = advanceStringIndex2(S, q, unicodeMatching);
+          if (z === null || (e = min3(toLength6(splitter.lastIndex + (SUPPORTS_Y ? 0 : q)), S.length)) === p) {
+            q = advanceStringIndex3(S, q, unicodeMatching);
          } else {
            A.push(S.slice(p, q));
            if (A.length === lim)
@@ -7725,6 +7776,12 @@
    el.removeChild(div);
    return linkColor;
  }
+  function isBS3() {
+    if (!import_jquery5.default.fn.tooltip) {
+      return false;
+    }
+    return import_jquery5.default.fn.tooltip.Constructor.VERSION.match(/^3\./);
+  }

  // src/shiny.ts
  var Shiny;
@@ -7855,9 +7912,9 @@
  var $22 = require_export();
  var fails6 = require_fails();
  var ArrayBufferModule = require_array_buffer();
-  var anObject4 = require_an_object();
+  var anObject5 = require_an_object();
  var toAbsoluteIndex3 = require_to_absolute_index();
-  var toLength6 = require_to_length();
+  var toLength7 = require_to_length();
  var speciesConstructor2 = require_species_constructor();
  var ArrayBuffer3 = ArrayBufferModule.ArrayBuffer;
  var DataView2 = ArrayBufferModule.DataView;
@@ -7868,12 +7925,12 @@
  $22({target: "ArrayBuffer", proto: true, unsafe: true, forced: INCORRECT_SLICE}, {
    slice: function slice2(start, end) {
      if (nativeArrayBufferSlice !== void 0 && end === void 0) {
-        return nativeArrayBufferSlice.call(anObject4(this), start);
+        return nativeArrayBufferSlice.call(anObject5(this), start);
      }
-      var length = anObject4(this).byteLength;
+      var length = anObject5(this).byteLength;
      var first = toAbsoluteIndex3(start, length);
      var fin = toAbsoluteIndex3(end === void 0 ? length : end, length);
-      var result = new (speciesConstructor2(this, ArrayBuffer3))(toLength6(fin - first));
+      var result = new (speciesConstructor2(this, ArrayBuffer3))(toLength7(fin - first));
      var viewSource = new DataView2(this);
      var viewTarget = new DataView2(result);
      var index = 0;
@@ -7991,46 +8048,6 @@
  var j;
  var key;

-  // node_modules/core-js/modules/es.string.match.js
-  "use strict";
-  var fixRegExpWellKnownSymbolLogic3 = require_fix_regexp_well_known_symbol_logic();
-  var anObject5 = require_an_object();
-  var toLength7 = require_to_length();
-  var requireObjectCoercible3 = require_require_object_coercible();
-  var advanceStringIndex3 = require_advance_string_index();
-  var regExpExec2 = require_regexp_exec_abstract();
-  fixRegExpWellKnownSymbolLogic3("match", 1, function(MATCH, nativeMatch, maybeCallNative) {
-    return [
-      function match(regexp) {
-        var O = requireObjectCoercible3(this);
-        var matcher = regexp == void 0 ? void 0 : regexp[MATCH];
-        return matcher !== void 0 ? matcher.call(regexp, O) : new RegExp(regexp)[MATCH](String(O));
-      },
-      function(regexp) {
-        var res = maybeCallNative(nativeMatch, regexp, this);
-        if (res.done)
-          return res.value;
-        var rx = anObject5(regexp);
-        var S = String(this);
-        if (!rx.global)
-          return regExpExec2(rx, S);
-        var fullUnicode = rx.unicode;
-        rx.lastIndex = 0;
-        var A = [];
-        var n = 0;
-        var result;
-        while ((result = regExpExec2(rx, S)) !== null) {
-          var matchStr = String(result[0]);
-          A[n] = matchStr;
-          if (matchStr === "")
-            rx.lastIndex = advanceStringIndex3(S, toLength7(rx.lastIndex), fullUnicode);
-          n++;
-        }
-        return n === 0 ? null : A;
-      }
-    ];
-  });
-
  // node_modules/core-js/modules/es.string.search.js
  "use strict";
  var fixRegExpWellKnownSymbolLogic4 = require_fix_regexp_well_known_symbol_logic();
--- a/inst/www/shared/shiny.js.map
+++ b/inst/www/shared/shiny.js.map
--- a/inst/www/shared/shiny.min.js
+++ b/inst/www/shared/shiny.min.js
--- a/inst/www/shared/shiny.min.js.map
+++ b/inst/www/shared/shiny.min.js.map
--- a/man/navlistPanel.Rd
+++ b/man/navlistPanel.Rd
@@ -8,6 +8,8 @@ navlistPanel(
  ...,
  id = NULL,
  selected = NULL,
+  header = NULL,
+  footer = NULL,
  well = TRUE,
  fluid = TRUE,
  widths = c(4, 8)
@@ -25,13 +27,19 @@ value will correspond to the \code{value} argument that is passed to
 of the navigation item that should be selected by default. If \code{NULL},
 the first navigation will be selected.}

+\item{header}{Tag or list of tags to display as a common header above all
+tabPanels.}
+
+\item{footer}{Tag or list of tags to display as a common footer below all
+tabPanels}
+
 \item{well}{\code{TRUE} to place a well (gray rounded rectangle) around the
 navigation list.}

 \item{fluid}{\code{TRUE} to use fluid layout; \code{FALSE} to use fixed
 layout.}

-\item{widths}{Column withs of the navigation list and tabset content areas
+\item{widths}{Column widths of the navigation list and tabset content areas
 respectively.}
 }
 \description{
--- a/man/tabsetPanel.Rd
+++ b/man/tabsetPanel.Rd
@@ -9,6 +9,8 @@ tabsetPanel(
  id = NULL,
  selected = NULL,
  type = c("tabs", "pills", "hidden"),
+  header = NULL,
+  footer = NULL,
  position = deprecated()
 )
 }
@@ -32,6 +34,12 @@ conjunction with \code{\link[=tabPanelBody]{tabPanelBody()}} and \code{\link[=up
 active tab via other input controls. (See example below)}
 }}

+\item{header}{Tag or list of tags to display as a common header above all
+tabPanels.}
+
+\item{footer}{Tag or list of tags to display as a common footer below all
+tabPanels}
+
 \item{position}{This argument is deprecated; it has been discontinued in
 Bootstrap 3.}
 }
--- a/srcts/src/main.ts
+++ b/srcts/src/main.ts
@@ -34,6 +34,7 @@ import {
  updateLabel,
  getComputedLinkColor,
  makeBlob,
+  isBS3,
 } from "./utils";

 import { isQt, isIE, IEVersion } from "./utils/browser";
@@ -1241,8 +1242,10 @@ function main(): void {
    function getTargetTabs($tabset, $tabContent, target) {
      const dataValue = "[data-value='" + $escape(target) + "']";
      const $aTag = $tabset.find("a" + dataValue);
-      const $liTag = $aTag.parent();
+      let $liTag = $aTag.parent("li");
+      // BS3 dropdown anchors are wrapped in <li>, but they can't be in BS4

+      if ($liTag.length === 0) $liTag = $aTag;
      if ($liTag.length === 0) {
        throw (
          "There is no tabPanel (or navbarMenu) with value" +
@@ -1259,10 +1262,12 @@ function main(): void {
        const $dropdownTabset = $aTag.find("+ ul.dropdown-menu");
        const dropdownId = $dropdownTabset.attr("data-tabsetid");

-        const $dropdownLiTags = $dropdownTabset
-          .find("a[data-toggle='tab']")
-          .parent("li");
+        let $dropdownLiTags = $dropdownTabset.find("a[data-toggle='tab']");
+        // BS3 dropdown anchors are wrapped in <li>, but they can't be in BS4

+        if ($dropdownLiTags.parent("li").length > 0) {
+          $dropdownLiTags = $dropdownLiTags.parent("li");
+        }
        $dropdownLiTags.each(function (i, el) {
          $liTags.push($(el));
        });
@@ -1286,7 +1291,7 @@ function main(): void {
      let tabsetId = $parentTabset.attr("data-tabsetid");

      const $divTag = $(message.divTag.html);
-      const $liTag = $(message.liTag.html);
+      let $liTag = $(message.liTag.html);
      const $aTag = $liTag.find("> a");

      // Unless the item is being prepended/appended, the target tab
@@ -1297,6 +1302,12 @@ function main(): void {
      if (message.target !== null) {
        target = getTargetTabs($tabset, $tabContent, message.target);
        $targetLiTag = target.$liTag;
+        // If the target is a (BS4) .dropdown-item, then we can't insert
+        // <li class='nav-item'><a class='nav-link'>...</a></li>,
+        // instead, we need <a class='dropdown-item'>...</a>
+        if ($targetLiTag.hasClass("dropdown-item")) {
+          $liTag = $aTag.removeClass("nav-link").addClass("dropdown-item");
+        }
      }

      // If the item is to be placed inside a navbarMenu (dropdown),
@@ -1321,7 +1332,11 @@ function main(): void {
        const index = getTabIndex($tabset, tabsetId);
        const tabId = "tab-" + tabsetId + "-" + index;

-        $liTag.find("> a").attr("href", "#" + tabId);
+        let anchor = $liTag.find("> a");
+        // BS3 dropdown anchors are wrapped in <li>, but they can't be in BS4
+
+        if (anchor.length === 0) anchor = $liTag;
+        anchor.attr("href", "#" + tabId);
        $divTag.attr("id", tabId);
      }

@@ -1411,8 +1426,8 @@ function main(): void {
        // loop through all existing tabs, find the one with highest id
        // (since this is based on a numeric counter), and increment

-        $tabset.find("> li").each(function () {
-          const $tab = $(this).find("> a[data-toggle='tab']");
+        $tabset.find("a[data-toggle='tab']").each(function () {
+          const $tab = $(this);

          if ($tab.length > 0) {
            // remove leading url if it exists. (copy of bootstrap url stripper)
@@ -5881,7 +5896,12 @@ function main(): void {
      return $(scope).find("ul.nav.shiny-tab-input");
    },
    getValue: function (el) {
-      const anchor = $(el).find("li:not(.dropdown).active").children("a");
+      // prettier-ignore
+      let anchor = isBS3()
+        ? $(el).find("li:not(.dropdown).active > a")
+        : $(el).find(
+          ".nav-link:not(.dropdown-toggle).active, .dropdown-menu > .dropdown-item.active"
+        );

      if (anchor.length === 1) return this._getTabName(anchor);

@@ -5892,7 +5912,12 @@ function main(): void {
      let success = false;

      if (value) {
-        const anchors = $(el).find("li:not(.dropdown)").children("a");
+        // prettier-ignore
+        let anchors = isBS3()
+          ? $(el).find("li:not(.dropdown) > a")
+          : $(el).find(
+            ".nav-link:not(.dropdown-toggle), .dropdown-menu > .dropdown-item"
+          );

        anchors.each(function () {
          if (self._getTabName($(this)) === value) {
--- a/srcts/src/utils/index.ts
+++ b/srcts/src/utils/index.ts
@@ -361,6 +361,17 @@ function getComputedLinkColor(el: HTMLElement): string {
  return linkColor;
 }

+function isBS3(): boolean {
+  // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+  // @ts-ignore
+  if (!$.fn.tooltip) {
+    return false;
+  }
+  // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+  // @ts-ignore
+  return $.fn.tooltip.Constructor.VERSION.match(/^3\./);
+}
+
 export {
  escapeHTML,
  randomId,
@@ -384,4 +395,5 @@ export {
  updateLabel,
  getComputedLinkColor,
  makeBlob,
+  isBS3,
 };
--- a/tests/testthat/_snaps/tabPanel.md
+++ b/tests/testthat/_snaps/tabPanel.md
@@ -0,0 +1,339 @@
+# tabsetPanel() markup is correct
+
+    Code
+      default
+    Output
+      <div class="tabbable">
+        <ul class="nav nav-tabs" data-tabsetid="4785">
+          <li class="active">
+            <a href="#tab-4785-1" data-toggle="tab" data-value="A">A</a>
+          </li>
+          <li>
+            <a href="#tab-4785-2" data-toggle="tab" data-value="B">
+              <i class=" fab fa-github fa-fw" role="presentation" aria-label=" icon"></i>
+              B
+            </a>
+          </li>
+          <li class="dropdown">
+            <a href="#" class="dropdown-toggle" data-toggle="dropdown" data-value="Menu">
+              Menu
+              <b class="caret"></b>
+            </a>
+            <ul class="dropdown-menu" data-tabsetid="1502">
+              <li>
+                <a href="#tab-1502-1" data-toggle="tab" data-value="C">C</a>
+              </li>
+            </ul>
+          </li>
+        </ul>
+        <div class="tab-content" data-tabsetid="4785">
+          <div class="tab-pane active" data-value="A" id="tab-4785-1">a</div>
+          <div class="tab-pane" data-value="B" data-icon-class="fab fa-github" id="tab-4785-2">b</div>
+          <div class="tab-pane" data-value="C" id="tab-1502-1">c</div>
+        </div>
+      </div>
+
+---
+
+    Code
+      pills
+    Output
+      <div class="tabbable">
+        <ul class="nav nav-pills" data-tabsetid="4785">
+          <li>
+            <a href="#tab-4785-1" data-toggle="tab" data-value="A">A</a>
+          </li>
+          <li class="active">
+            <a href="#tab-4785-2" data-toggle="tab" data-value="B">
+              <i class=" fab fa-github fa-fw" role="presentation" aria-label=" icon"></i>
+              B
+            </a>
+          </li>
+          <li class="dropdown">
+            <a href="#" class="dropdown-toggle" data-toggle="dropdown" data-value="Menu">
+              Menu
+              <b class="caret"></b>
+            </a>
+            <ul class="dropdown-menu" data-tabsetid="1502">
+              <li>
+                <a href="#tab-1502-1" data-toggle="tab" data-value="C">C</a>
+              </li>
+            </ul>
+          </li>
+        </ul>
+        <div class="content-header"></div>
+        <div class="tab-content" data-tabsetid="4785">
+          <div class="tab-pane" data-value="A" id="tab-4785-1">a</div>
+          <div class="tab-pane active" data-icon-class="fab fa-github" data-value="B" id="tab-4785-2">b</div>
+          <div class="tab-pane" data-value="C" id="tab-1502-1">c</div>
+        </div>
+        <div class="content-footer"></div>
+      </div>
+
+---
+
+    Code
+      bslib_tags(x)
+    Output
+      <div class="tabbable">
+        <ul class="nav nav-tabs" data-tabsetid="4785">
+          <li class="nav-item">
+            <a class="nav-link active" data-toggle="tab" data-value="A" href="#tab-4785-1">A</a>
+          </li>
+          <li class="nav-item">
+            <a class="nav-link" href="#tab-4785-2" data-toggle="tab" data-value="B">
+              <i class=" fab fa-github fa-fw" role="presentation" aria-label=" icon"></i>
+              B
+            </a>
+          </li>
+          <li class="dropdown nav-item">
+            <a class="dropdown-toggle nav-link" data-toggle="dropdown" data-value="Menu" href="#">
+              Menu
+              <b class="caret"></b>
+            </a>
+            <ul class="dropdown-menu" data-tabsetid="1502">
+              <a class="dropdown-item" href="#tab-1502-1" data-toggle="tab" data-value="C">C</a>
+            </ul>
+          </li>
+        </ul>
+        <div class="tab-content" data-tabsetid="4785">
+          <div class="tab-pane active" data-value="A" id="tab-4785-1">a</div>
+          <div class="tab-pane" data-value="B" data-icon-class="fab fa-github" id="tab-4785-2">b</div>
+          <div class="tab-pane" data-value="C" id="tab-1502-1">c</div>
+        </div>
+      </div>
+
+---
+
+    Code
+      bslib_tags(x)
+    Output
+      <div class="tabbable">
+        <ul class="nav nav-pills" data-tabsetid="4785">
+          <li class="nav-item">
+            <a class="nav-link" href="#tab-4785-1" data-toggle="tab" data-value="A">A</a>
+          </li>
+          <li class="nav-item">
+            <a class="nav-link active" data-toggle="tab" data-value="B" href="#tab-4785-2">
+              <i class=" fab fa-github fa-fw" role="presentation" aria-label=" icon"></i>
+              B
+            </a>
+          </li>
+          <li class="dropdown nav-item">
+            <a class="dropdown-toggle nav-link" data-toggle="dropdown" data-value="Menu" href="#">
+              Menu
+              <b class="caret"></b>
+            </a>
+            <ul class="dropdown-menu" data-tabsetid="1502">
+              <a class="dropdown-item" href="#tab-1502-1" data-toggle="tab" data-value="C">C</a>
+            </ul>
+          </li>
+        </ul>
+        <div class="content-header"></div>
+        <div class="tab-content" data-tabsetid="4785">
+          <div class="tab-pane" data-value="A" id="tab-4785-1">a</div>
+          <div class="tab-pane active" data-icon-class="fab fa-github" data-value="B" id="tab-4785-2">b</div>
+          <div class="tab-pane" data-value="C" id="tab-1502-1">c</div>
+        </div>
+        <div class="content-footer"></div>
+      </div>
+
+# navbarPage() markup is correct
+
+    Code
+      nav_page
+    Output
+      <nav class="navbar navbar-default navbar-static-top" role="navigation">
+        <div class="container-fluid">
+          <div class="navbar-header">
+            <span class="navbar-brand">Title</span>
+          </div>
+          <ul class="nav navbar-nav" data-tabsetid="4785">
+            <li class="active">
+              <a href="#tab-4785-1" data-toggle="tab" data-value="A">A</a>
+            </li>
+            <li>
+              <a href="#tab-4785-2" data-toggle="tab" data-value="B">
+                <i class=" fab fa-github fa-fw" role="presentation" aria-label=" icon"></i>
+                B
+              </a>
+            </li>
+            <li class="dropdown">
+              <a href="#" class="dropdown-toggle" data-toggle="dropdown" data-value="Menu">
+                Menu
+                <b class="caret"></b>
+              </a>
+              <ul class="dropdown-menu" data-tabsetid="1502">
+                <li>
+                  <a href="#tab-1502-1" data-toggle="tab" data-value="C">C</a>
+                </li>
+              </ul>
+            </li>
+          </ul>
+        </div>
+      </nav>
+      <div class="container-fluid">
+        <div class="tab-content" data-tabsetid="4785">
+          <div class="tab-pane active" data-value="A" id="tab-4785-1">a</div>
+          <div class="tab-pane" data-value="B" data-icon-class="fab fa-github" id="tab-4785-2">b</div>
+          <div class="tab-pane" data-value="C" id="tab-1502-1">c</div>
+        </div>
+      </div>
+
+---
+
+    Code
+      bslib_tags(x)
+    Output
+      <nav class="navbar navbar-default navbar-static-top" role="navigation">
+        <div class="container-fluid">
+          <div class="navbar-header">
+            <span class="navbar-brand">Title</span>
+          </div>
+          <ul class="nav navbar-nav" data-tabsetid="4785">
+            <li class="nav-item">
+              <a class="nav-link active" data-toggle="tab" data-value="A" href="#tab-4785-1">A</a>
+            </li>
+            <li class="nav-item">
+              <a class="nav-link" href="#tab-4785-2" data-toggle="tab" data-value="B">
+                <i class=" fab fa-github fa-fw" role="presentation" aria-label=" icon"></i>
+                B
+              </a>
+            </li>
+            <li class="dropdown nav-item">
+              <a class="dropdown-toggle nav-link" data-toggle="dropdown" data-value="Menu" href="#">
+                Menu
+                <b class="caret"></b>
+              </a>
+              <ul class="dropdown-menu" data-tabsetid="1502">
+                <a class="dropdown-item" href="#tab-1502-1" data-toggle="tab" data-value="C">C</a>
+              </ul>
+            </li>
+          </ul>
+        </div>
+      </nav>
+      <div class="container-fluid">
+        <div class="tab-content" data-tabsetid="4785">
+          <div class="tab-pane active" data-value="A" id="tab-4785-1">a</div>
+          <div class="tab-pane" data-value="B" data-icon-class="fab fa-github" id="tab-4785-2">b</div>
+          <div class="tab-pane" data-value="C" id="tab-1502-1">c</div>
+        </div>
+      </div>
+
+# String input is handled properly
+
+    Code
+      nav_list
+    Output
+      <div class="row">
+        <div class="col-sm-4 well">
+          <ul class="nav nav-pills nav-stacked" data-tabsetid="4785">
+            <li class="navbar-brand">A header</li>
+            <li class="active">
+              <a href="#tab-4785-2" data-toggle="tab" data-value="A">A</a>
+            </li>
+            <li>
+              <a href="#tab-4785-3" data-toggle="tab" data-value="B">
+                <i class=" fab fa-github fa-fw" role="presentation" aria-label=" icon"></i>
+                B
+              </a>
+            </li>
+            <li class="dropdown">
+              <a href="#" class="dropdown-toggle" data-toggle="dropdown" data-value="Menu">
+                Menu
+                <b class="caret"></b>
+              </a>
+              <ul class="dropdown-menu" data-tabsetid="1502">
+                <li>
+                  <a href="#tab-1502-1" data-toggle="tab" data-value="C">C</a>
+                </li>
+              </ul>
+            </li>
+          </ul>
+        </div>
+        <div class="col-sm-8">
+          <div class="tab-content" data-tabsetid="4785">
+            <div class="tab-pane active" data-value="A" id="tab-4785-2">a</div>
+            <div class="tab-pane" data-value="B" data-icon-class="fab fa-github" id="tab-4785-3">b</div>
+            <div class="tab-pane" data-value="C" id="tab-1502-1">c</div>
+          </div>
+        </div>
+      </div>
+
+---
+
+    Code
+      bslib_tags(x)
+    Output
+      <div class="row">
+        <div class="col-sm-4 well">
+          <ul class="nav nav-pills nav-stacked" data-tabsetid="4785">
+            <li class="navbar-brand">A header</li>
+            <li class="nav-item">
+              <a class="nav-link active" data-toggle="tab" data-value="A" href="#tab-4785-2">A</a>
+            </li>
+            <li class="nav-item">
+              <a class="nav-link" href="#tab-4785-3" data-toggle="tab" data-value="B">
+                <i class=" fab fa-github fa-fw" role="presentation" aria-label=" icon"></i>
+                B
+              </a>
+            </li>
+            <li class="dropdown nav-item">
+              <a class="dropdown-toggle nav-link" data-toggle="dropdown" data-value="Menu" href="#">
+                Menu
+                <b class="caret"></b>
+              </a>
+              <ul class="dropdown-menu" data-tabsetid="1502">
+                <a class="dropdown-item" href="#tab-1502-1" data-toggle="tab" data-value="C">C</a>
+              </ul>
+            </li>
+          </ul>
+        </div>
+        <div class="col-sm-8">
+          <div class="tab-content" data-tabsetid="4785">
+            <div class="tab-pane active" data-value="A" id="tab-4785-2">a</div>
+            <div class="tab-pane" data-value="B" data-icon-class="fab fa-github" id="tab-4785-3">b</div>
+            <div class="tab-pane" data-value="C" id="tab-1502-1">c</div>
+          </div>
+        </div>
+      </div>
+
+# Shiny.tag input produces a warning
+
+    Code
+      tab_tags
+    Output
+      <div class="tabbable">
+        <ul class="nav nav-tabs" data-tabsetid="4785">
+          <li class="active">
+            <a href="#tab-4785-1" data-toggle="tab"></a>
+          </li>
+          <li>
+            <a href="#tab-4785-2" data-toggle="tab" data-value="A">A</a>
+          </li>
+          <li>
+            <a href="#tab-4785-3" data-toggle="tab" data-value="B">
+              <i class=" fab fa-github fa-fw" role="presentation" aria-label=" icon"></i>
+              B
+            </a>
+          </li>
+          <li class="dropdown">
+            <a href="#" class="dropdown-toggle" data-toggle="dropdown" data-value="Menu">
+              Menu
+              <b class="caret"></b>
+            </a>
+            <ul class="dropdown-menu" data-tabsetid="1502">
+              <li>
+                <a href="#tab-1502-1" data-toggle="tab" data-value="C">C</a>
+              </li>
+            </ul>
+          </li>
+        </ul>
+        <div class="tab-content" data-tabsetid="4785">
+          <div class="active" id="tab-4785-1">A div</div>
+          <div class="tab-pane" data-value="A" id="tab-4785-2">a</div>
+          <div class="tab-pane" data-value="B" data-icon-class="fab fa-github" id="tab-4785-3">b</div>
+          <div class="tab-pane" data-value="C" id="tab-1502-1">c</div>
+        </div>
+      </div>
+
--- a/tests/testthat/test-tabPanel.R
+++ b/tests/testthat/test-tabPanel.R
@@ -1,4 +1,87 @@
+# tabsetPanel() et al. use p_randomInt() to generate ids (which uses withPrivateSeed()),
+# so we need to fix Shiny's private seed in order to make their HTML output deterministic
+navlist_panel <- function(...) {

+  withPrivateSeed(set.seed(100))
+  navlistPanel(...)
+}
+navbar_page <- function(...) {
+  withPrivateSeed(set.seed(100))
+  navbarPage(...)
+}
+tabset_panel <- function(...) {
+  withPrivateSeed(set.seed(100))
+  tabsetPanel(...)
+}
+
+expect_snapshot2 <- function(...) {
+  if (getRversion() < "3.6.0") {
+    skip("Skipping snapshots on R < 3.6 because of different RNG method")
+  }
+  expect_snapshot(...)
+}
+
+expect_snapshot_bslib <- function(x, ...) {
+  expect_snapshot2(bslib_tags(x), ...)
+}
+
+# Simulates the UI tags that would be produced by
+# shinyApp(bootstrapPage(theme), function(...) {})
+bslib_tags <- function(ui, theme = bslib::bs_theme()) {
+  old_theme <- getCurrentTheme()
+  on.exit(setCurrentTheme(old_theme), add = TRUE)
+  setCurrentTheme(theme)
+  htmltools::renderTags(ui)$html
+}
+
+panels <- list(
+  tabPanel("A", "a"),
+  tabPanel("B", "b", icon = icon("github")),
+  navbarMenu("Menu", tabPanel("C", "c"))
+)
+
+test_that("tabsetPanel() markup is correct", {
+
+  default <- tabset_panel(!!!panels)
+  pills <- tabset_panel(
+    !!!panels, type = "pills", selected = "B",
+    header = div(class = "content-header"),
+    footer = div(class = "content-footer")
+  )
+  # BS3
+  expect_snapshot2(default)
+  expect_snapshot2(pills)
+  # BS4
+  expect_snapshot_bslib(default)
+  expect_snapshot_bslib(pills)
+})
+
+test_that("navbarPage() markup is correct", {
+  nav_page <- navbar_page("Title", !!!panels)
+  expect_snapshot2(nav_page)
+  expect_snapshot_bslib(nav_page)
+})
+
+# navlistPanel() can handle strings, but the others can't
+test_that("String input is handled properly", {
+  nav_list <- navlist_panel(!!!c(list("A header"), panels))
+  expect_snapshot2(nav_list)
+  expect_snapshot_bslib(nav_list)
+  expect_error(
+    tabsetPanel(!!!c(list("A header"), panels)),
+    "tabPanel"
+  )
+})
+
+test_that("Shiny.tag input produces a warning", {
+  panels3 <- c(list(div("A div")), panels)
+  tab_tags <- expect_warning(tabset_panel(!!!panels3))
+  # Carson March 12th, 2021: Yes, he 'empty nav' output here isn't
+  # sensible (which is why we now throw a warning), but it's probably
+  # too late to change the behavior (it could break user code to do
+  # anything different)
+  expect_snapshot2(tab_tags)
+})

 test_that("tabPanelBody validates it's input", {
  expect_silent(tabPanelBody("a", "content1", "content2", icon = icon("table")))