Update window title when a pane item's title changes

spec/app/pane-spec.coffee

@@ -363,6 +363,24 @@ describe "Pane", ->
       pane.trigger 'pane:show-item-9' # don't fail on out-of-bounds indices
       expect(pane.activeItem).toBe pane.itemAtIndex(0)
 
+  describe "when the title of the active item changes", ->
+    it "emits pane:active-item-title-changed", ->
+      activeItemTitleChangedHandler = jasmine.createSpy("activeItemTitleChangedHandler")
+      pane.on 'pane:active-item-title-changed', activeItemTitleChangedHandler
+
+      expect(pane.activeItem).toBe view1
+
+      view2.trigger 'title-changed'
+      expect(activeItemTitleChangedHandler).not.toHaveBeenCalled()
+
+      view1.trigger 'title-changed'
+      expect(activeItemTitleChangedHandler).toHaveBeenCalled()
+      activeItemTitleChangedHandler.reset()
+
+      pane.showItem(view2)
+      view2.trigger 'title-changed'
+      expect(activeItemTitleChangedHandler).toHaveBeenCalled()
+
   describe ".remove()", ->
     it "destroys all the pane's items", ->
       pane.remove()

spec/app/root-view-spec.coffee

@@ -159,7 +159,7 @@ describe "RootView", ->
         rootView.trigger(event)
         expect(commandHandler).toHaveBeenCalled()
 
-  describe "title", ->
+  describe "window title", ->
     describe "when the project has no path", ->
       it "sets the title to 'untitled'", ->
         project.setPath(undefined)
@@ -174,6 +174,12 @@ describe "RootView", ->
           item = rootView.getActivePaneItem()
           expect(rootView.title).toBe "#{item.getTitle()} - #{project.getPath()}"
 
+      describe "when the title of the active pane item changes", ->
+        it "updates the window title based on the item's new title", ->
+          editSession = rootView.getActivePaneItem()
+          editSession.buffer.setPath('/tmp/hi')
+          expect(rootView.title).toBe "#{editSession.getTitle()} - #{project.getPath()}"
+
       describe "when the active pane's item changes", ->
         it "updates the title to the new item's title plus the project path", ->
           rootView.getActivePane().showNextItem()

src/app/pane.coffee

@@ -94,10 +94,13 @@ class Pane extends View
   showItem: (item) ->
     return if !item? or item is @activeItem
 
-    @autosaveActiveItem() if @activeItem
+    if @activeItem
+      @activeItem.off? 'title-changed', @activeItemTitleChanged
+      @autosaveActiveItem()
 
     isFocused = @is(':has(:focus)')
     @addItem(item)
+    item.on? 'title-changed', @activeItemTitleChanged
     view = @viewForItem(item)
     @itemViews.children().not(view).hide()
     @itemViews.append(view) unless view.parent().is(@itemViews)
@@ -107,6 +110,9 @@ class Pane extends View
     @activeView = view
     @trigger 'pane:active-item-changed', [item]
 
+  activeItemTitleChanged: =>
+    @trigger 'pane:active-item-title-changed'
+
   addItem: (item) ->
     return if _.include(@items, item)
     index = @getActiveItemIndex() + 1

src/app/root-view.coffee

@@ -32,8 +32,6 @@ class RootView extends View
     panes = deserialize(panesViewState) if panesViewState?.deserializer is 'PaneContainer'
     new RootView({panes})
 
-  title: null
-
   initialize: ->
     @command 'toggle-dev-tools', => atom.toggleDevTools()
     @on 'focus', (e) => @handleFocus(e)
@@ -44,6 +42,7 @@ class RootView extends View
     @on 'pane:became-active', => @updateTitle()
     @on 'pane:active-item-changed', '.active.pane', => @updateTitle()
     @on 'pane:removed', => @updateTitle() unless @getActivePane()
+    @on 'pane:active-item-title-changed', '.active.pane', => @updateTitle()
 
     @command 'window:increase-font-size', =>
       config.set("editor.fontSize", config.get("editor.fontSize") + 1)