Pasting widgets with the clipboard plugin under firefox removes some classes.

[Nikolay Ch]

Steps to reproduce

1. Open the ckeditor with firefox, copy a widget with more html.
2. Click right button on the editor, then paste from the dropdown.
3. The paste dialog is shown, then press Ctrl+V to paste it in the dialog and click OK.

Expected result

The widget should be inserted with all its classes, same content, and same styles.

Actual result

All elements are present but some of their classes are removed, the style is not the same. I've debugged the paste dialog and in the event editor.fire( 'pasteDialogCommit', { dataValue: html }) - the dataValue contains all necessary elements and their classes. However when the widget is inserted and I inspect its elements it seems some of their classes are removed.

Other details (browser, OS, CKEditor version, installed plugins)

It works perfectly under chrome, IE and Safari.

[Jakub Ś]

Please provide sample and plugin which produces such problem. I have just tried experimenting with simplebox (I have allowed many extra styles, attributes and classes) but no problem occurred.