Trigger 'pane:active-item-changed' on Pane

This event is triggered when the item changes on the active pane, or
when a different pane becomes active.

Also: Pane now sets itself as the active pane, rather than letting
PaneContainer handle the focusin event.

spec/app/pane-spec.coffee

@@ -27,6 +27,27 @@ describe "Pane", ->
       expect(view2.css('display')).toBe ''
       expect(pane.currentItem).toBe view2
 
+    it "triggers 'pane:active-item-changed' if the pane is active and the item isn't already the currentItem", ->
+      pane.makeActive()
+      itemChangedHandler = jasmine.createSpy("itemChangedHandler")
+      container.on 'pane:active-item-changed', itemChangedHandler
+
+      expect(pane.currentItem).toBe view1
+      pane.showItem(view2)
+      pane.showItem(view2)
+      expect(itemChangedHandler.callCount).toBe 1
+      expect(itemChangedHandler.argsForCall[0][1]).toBe view2
+      itemChangedHandler.reset()
+
+      pane.showItem(editSession1)
+      expect(itemChangedHandler).toHaveBeenCalled()
+      expect(itemChangedHandler.argsForCall[0][1]).toBe editSession1
+      itemChangedHandler.reset()
+
+      pane.makeInactive()
+      pane.showItem(editSession2)
+      expect(itemChangedHandler).not.toHaveBeenCalled()
+
     describe "when the given item isn't yet in the items list on the pane", ->
       it "adds it to the items list after the current item", ->
         view3 = $$ -> @div id: 'view-3', "View 3"
@@ -130,6 +151,18 @@ describe "Pane", ->
       pane.focus()
       expect(focusHandler).toHaveBeenCalled()
 
+    it "triggers 'pane:active-item-changed' if it was not previously active", ->
+      itemChangedHandler = jasmine.createSpy("itemChangedHandler")
+      container.on 'pane:active-item-changed', itemChangedHandler
+
+      expect(pane.isActive()).toBeFalsy()
+      pane.focusin()
+      expect(pane.isActive()).toBeTruthy()
+      pane.focusin()
+
+      expect(itemChangedHandler.callCount).toBe 1
+      expect(itemChangedHandler.argsForCall[0][1]).toBe pane.currentItem
+
   describe "split methods", ->
     [pane1, view3, view4] = []
     beforeEach ->

src/app/pane-container.coffee

@@ -13,11 +13,6 @@ class PaneContainer extends View
   @content: ->
     @div id: 'panes'
 
-  initialize: ->
-    @on 'focusin', (e) =>
-      focusedPane = $(e.target).closest('.pane').view()
-      @setActivePane(focusedPane)
-
   serialize: ->
     deserializer: 'PaneContainer'
     root: @getRoot()?.serialize()
@@ -40,9 +35,6 @@ class PaneContainer extends View
   getActivePane: ->
     @find('.pane.active').view() ? @find('.pane:first').view()
 
-  setActivePane: (pane) ->
-    @find('.pane').removeClass('active')
-    pane.addClass('active')
 
   adjustPaneDimensions: ->
     if root = @getRoot()

src/app/pane.coffee

@@ -27,9 +27,21 @@ class Pane extends View
     @command 'pane:split-right', => @splitRight()
     @command 'pane:split-up', => @splitUp()
     @command 'pane:split-down', => @splitDown()
-    @on 'focus', =>
-      @viewForCurrentItem().focus()
-      false
+    @on 'focus', => @currentView.focus(); false
+    @on 'focusin', => @makeActive()
+
+  makeActive: ->
+    for pane in @getContainer().getPanes() when pane isnt this
+      pane.makeInactive()
+    wasActive = @isActive()
+    @addClass('active')
+    @trigger 'pane:active-item-changed', [@currentItem] unless wasActive
+
+  makeInactive: ->
+    @removeClass('active')
+
+  isActive: ->
+    @hasClass('active')
 
   getItems: ->
     new Array(@items...)
@@ -55,6 +67,7 @@ class Pane extends View
     @showItem(@items[index])
 
   showItem: (item) ->
+    return if item is @currentItem
     @addItem(item)
     @itemViews.children().hide()
     view = @viewForItem(item)
@@ -62,6 +75,7 @@ class Pane extends View
     @currentItem = item
     @currentView = view
     @currentView.show()
+    @trigger 'pane:active-item-changed', [item] if @isActive()
 
   addItem: (item) ->
     return if _.include(@items, item)