JavaScriptException in undo/plugin.js

[wginolas]

We have the following issue, when we combine IE, inline editing and the codesnippt plugin.

1. Use IE
2. Insert a Code-Snippet and enter some code.
3. Do not move the cursor out of the code snippet.
4. Close the editor, i.e. call ckeditor.destroy().

The following exception is thrown:

 TypeError: Object doesn't support property or method 'replace'
   at Image (http://kartoffel/toro/ckeditor/plugins/undo/plugin.js:788:5)
   at lock (http://kartoffel/toro/ckeditor/plugins/undo/plugin.js:625:7)
   at Anonymous function (http://kartoffel/toro/ckeditor/plugins/undo/plugin.js:170:5)
   at listenerFirer (http://kartoffel/toro/ckeditor/core/event.js:144:6)
   at Anonymous function (http://kartoffel/toro/ckeditor/core/event.js:290:10)
   at fire (http://kartoffel/toro/ckeditor/core/editor_basic.js:24:3)
   at removeHiddenSelectionContainer (http://kartoffel/toro/ckeditor/core/selection.js:265:4)
   at reset (http://kartoffel/toro/ckeditor/core/selection.js:1670:6)
   at unlock (http://kartoffel/toro/ckeditor/core/selection.js:1634:4)
   at unlockSelection (http://kartoffel/toro/ckeditor/core/selection.js:977:4) 

I debugged into the code and noticed, that the editor.getSnapshot() function sometimes returns the boolean value true instead of a string. Especially, when the ckeditor is shutting down currently. undo/plugin.js:788:5 breaks when a boolean is retuned by getSnapshot().