Editors in #panes are always contained by .pane wrappers

This prepares us to refactor the split view and editor state code into Column, Row, and Pane objects.

src/app/editor.coffee

@@ -506,15 +506,17 @@ class Editor extends View
   split: (axis, side) ->
     return unless rootView = @rootView()
     editor = new Editor(@getEditorState())
-    rootView.addPane(editor, this, axis, side)
+    rootView.addPane(editor, this.parent(), axis, side)
 
   remove: (selector, keepData) ->
     return super if keepData
     @unsubscribeFromBuffer()
     rootView = @rootView()
-    parent = @parent()
+    pane = @parent('.pane')
+    paneParent = pane.parent()
     super
-    parent.remove() if parent.is('.row:empty, .column:empty')
+    pane.remove()
+    paneParent.remove() if paneParent.is('.row:empty, .column:empty')
     rootView?.editorRemoved(this)
 
   unsubscribeFromBuffer: ->

src/app/pane.coffee

@@ -0,0 +1,5 @@
+module.exports =
+class Pane
+  @content: (view) ->
+    @div class: 'pane', =>
+      @subview 'view', view

src/app/root-view.coffee

@@ -10,6 +10,7 @@ FileFinder = require 'file-finder'
 Project = require 'project'
 VimMode = require 'vim-mode'
 CommandPanel = require 'command-panel'
+Pane = require 'pane'
 
 module.exports =
 class RootView extends View
@@ -79,11 +80,15 @@ class RootView extends View
     if editor.length
       editor.view()
     else
-      new Editor().appendTo(@panes).focus()
+      editor = new Editor
+      pane = new Pane(editor)
+      @panes.append(pane)
+      editor.focus()
+      editor
 
   getWindowState: (element = @panes.children(':eq(0)')) ->
-    if element.hasClass('editor')
-      ['editor', element.view().getEditorState()]
+    if element.hasClass('pane')
+      ['editor', element.view().content.getEditorState()]
     else if element.hasClass('row')
       ['row'].concat element.children().toArray().map (elt) =>
         @getWindowState($(elt))
@@ -100,8 +105,8 @@ class RootView extends View
 
     switch windowState.shift()
       when 'editor'
-        editor = new Editor(windowState[0])
-        parent.append(editor)
+        editor = new Editor(windowState...)
+        parent.append(new Pane(editor))
       when 'row'
         row = $$ -> @div class: 'row'
         parent.append row
@@ -119,7 +124,8 @@ class RootView extends View
     unless sibling.parent().hasClass(axis)
       container = $$ -> @div class: axis
       container.insertBefore(sibling).append(sibling.detach())
-    sibling[side](view)
+    pane = new Pane(view)
+    sibling[side](pane)
     @adjustSplitPanes()
     view