Detach instead of remove when moved item is the view

Moving an item that extended the jQuery object between panes
was previously wiping out all jQuery data since remove() was being
called on the view item instead of detach().

spec/app/pane-spec.coffee

@@ -257,6 +257,13 @@ describe "Pane", ->
         expect(pane2.getItems()).toEqual [view3, editSession1]
         expect(editSession1.destroyed).toBeFalsy()
 
+    describe "when the item is a jQuery object", ->
+      it "preserves data by detaching instead of removing", ->
+        view1.data('preservative', 1234)
+        pane.moveItemToPane(view1, pane2, 1)
+        pane2.showItemAtIndex(1)
+        expect(pane2.activeView.data('preservative')).toBe 1234
+
   describe "core:close", ->
     it "destroys the active item and does not bubble the event", ->
       containerCloseHandler = jasmine.createSpy("containerCloseHandler")

src/app/pane.coffee

@@ -214,7 +214,9 @@ class Pane extends View
     @trigger 'pane:item-moved', [item, newIndex]
 
   moveItemToPane: (item, pane, index) ->
+    @isMovingItem = true
     @removeItem(item)
+    @isMovingItem = false
     pane.addItem(item, index)
 
   itemForUri: (uri) ->
@@ -235,8 +237,12 @@ class Pane extends View
         delete @viewsByClassName[viewClass.name]
 
     if @items.length > 0
-      viewToRemove?.remove()
+      if @isMovingItem and item is viewToRemove
+        viewToRemove?.detach()
+      else
+        viewToRemove?.remove()
     else
+      viewToRemove?.detach() if @isMovingItem and item is viewToRemove
       @remove()
 
   viewForItem: (item) ->