Double clicking a file changes focus to editor. Double clicking a directory toggles expansion. Single clicking doesn't ever change focus away from tree view.

spec/extensions/tree-view-spec.coffee

@@ -123,25 +123,47 @@ describe "TreeView", ->
       expect(child.directory.subscriptionCount()).toBe 0
       expect(grandchild.directory.subscriptionCount()).toBe 0
 
-  describe "when a file is clicked", ->
-    it "opens it in the active editor, focuses it and selects it", ->
+  describe "when a file is single-clicked", ->
+    it "selects the files and opens it in the active editor, without changing focus", ->
       expect(rootView.activeEditor()).toBeUndefined()
 
-      sampleJs.click()
+      sampleJs.trigger clickEvent(originalEvent: { detail: 1 })
       expect(sampleJs).toHaveClass 'selected'
       expect(rootView.activeEditor().buffer.path).toBe require.resolve('fixtures/sample.js')
+      expect(rootView.activeEditor().isFocused).toBeFalsy()
 
-      sampleTxt.click()
+      sampleTxt.trigger clickEvent(originalEvent: { detail: 1 })
       expect(sampleTxt).toHaveClass 'selected'
       expect(treeView.find('.selected').length).toBe 1
       expect(rootView.activeEditor().buffer.path).toBe require.resolve('fixtures/sample.txt')
+      expect(rootView.activeEditor().isFocused).toBeFalsy()
 
-  describe "when a directory is clicked", ->
+  describe "when a file is double-clicked", ->
+    it "selects the file and opens it in the active editor on the first click, then changes focus to the active editor on the second", ->
+      sampleJs.trigger clickEvent(originalEvent: { detail: 1 })
+      expect(sampleJs).toHaveClass 'selected'
+      expect(rootView.activeEditor().buffer.path).toBe require.resolve('fixtures/sample.js')
+      expect(rootView.activeEditor().isFocused).toBeFalsy()
+
+      sampleJs.trigger clickEvent(originalEvent: { detail: 2 })
+      expect(rootView.activeEditor().isFocused).toBeTruthy()
+
+  describe "when a directory is single-clicked", ->
     it "is selected", ->
       subdir = treeView.root.find('.directory:first').view()
-      subdir.click()
+      subdir.trigger clickEvent(originalEvent: { detail: 1 })
       expect(subdir).toHaveClass 'selected'
 
+  describe "when a directory is double-clicked", ->
+    it "toggles the directory expansion state and does not change the focus to the editor", ->
+      sampleJs.trigger clickEvent(originalEvent: { detail: 1 })
+      subdir = treeView.root.find('.directory:first').view()
+      subdir.trigger clickEvent(originalEvent: { detail: 1 })
+      expect(subdir).toHaveClass 'selected'
+      subdir.trigger clickEvent(originalEvent: { detail: 2 })
+      expect(subdir).toHaveClass 'expanded'
+      expect(rootView.activeEditor().isFocused).toBeFalsy()
+
   describe "when a new file is opened in the active editor", ->
     it "is selected in the tree view if visible", ->
       sampleJs.click()

spec/spec-helper.coffee

@@ -71,9 +71,6 @@ window.keydownEvent = (pattern, properties={}) ->
   event.keystroke = (new Keymap).keystrokeStringForEvent(event)
   event
 
-window.clickEvent = (properties={}) ->
-  $.Event "click", properties
-
 window.mouseEvent = (type, properties) ->
   if properties.point
     {point, editor} = properties
@@ -83,6 +80,9 @@ window.mouseEvent = (type, properties) ->
   properties.originalEvent ?= {detail: 1}
   $.Event type, properties
 
+window.clickEvent = (properties={}) ->
+  window.mouseEvent("click", properties)
+
 window.mousedownEvent = (properties={}) ->
   window.mouseEvent('mousedown', properties)
 

src/app/root-view.coffee

@@ -94,7 +94,7 @@ class RootView extends View
     extension.deactivate() for name, extension of @extensions
     @remove()
 
-  open: (path) ->
+  open: (path, changeFocus=true) ->
     buffer = @project.open(path)
 
     if @activeEditor()
@@ -103,21 +103,25 @@ class RootView extends View
       editor = new Editor({ buffer })
       pane = new Pane(editor)
       @panes.append(pane)
-      editor.focus()
+      if changeFocus
+        editor.focus()
+      else
+        @makeEditorActive(editor)
 
   editorFocused: (editor) ->
-    if @panes.containsElement(editor)
-      previousActiveEditor = @panes.find('.editor.active').view()
-      previousActiveEditor?.removeClass('active').off('.root-view')
+    @makeEditorActive(editor) if @panes.containsElement(editor)
 
-      editor
-        .addClass('active')
-        .on 'editor-path-change.root-view', =>
-          @trigger 'active-editor-path-change', editor.buffer.path
-
-      if not previousActiveEditor or editor.buffer.path != previousActiveEditor.buffer.path
+  makeEditorActive: (editor) ->
+    previousActiveEditor = @panes.find('.editor.active').view()
+    previousActiveEditor?.removeClass('active').off('.root-view')
+    editor
+      .addClass('active')
+      .on 'editor-path-change.root-view', =>
         @trigger 'active-editor-path-change', editor.buffer.path
 
+    if not previousActiveEditor or editor.buffer.path != previousActiveEditor.buffer.path
+      @trigger 'active-editor-path-change', editor.buffer.path
+
   setTitle: (title='untitled') ->
     document.title = title
 

src/extensions/tree-view/tree-view.coffee

@@ -39,8 +39,15 @@ class TreeView extends View
   initialize: (@rootView) ->
     @on 'click', '.entry', (e) =>
       entry = $(e.currentTarget).view()
-      @selectEntry(entry)
-      @openSelectedEntry() if (entry instanceof FileView)
+      switch e.originalEvent?.detail ? 1
+        when 1
+          @selectEntry(entry)
+          @openSelectedEntry() if (entry instanceof FileView)
+        when 2
+          if entry.is('.selected.file')
+            @rootView.activeEditor().focus()
+          else if entry.is('.selected.directory')
+            entry.toggleExpansion()
       false
 
     @on 'move-up', => @moveUp()
@@ -119,8 +126,7 @@ class TreeView extends View
     if (selectedEntry instanceof DirectoryView)
       selectedEntry.view().toggleExpansion()
     else if (selectedEntry instanceof FileView)
-      @rootView.open(selectedEntry.getPath())
-      @rootView.focus()
+      @rootView.open(selectedEntry.getPath(), false)
 
   move: ->
     @rootView.append(new MoveDialog(@rootView.project, @selectedEntry().getPath()))

static/tree-view.css

@@ -7,6 +7,7 @@
   padding: 0 1em;
   cursor: default;
   font: 16px Inconsolata, Monaco, Courier !important;
+  -webkit-user-select: none;
 }
 
 .tree-view .disclosure-arrow {