User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:39.0) Gecko/20100101 Firefox/39.0 Build ID: 20150630154324 Steps to reproduce: See the attached test file: there are nested contenteditable regions in the document in a true -> false -> true fashion. 1. Open the attached file with Firefox version 39 2. Click on the text reading 'except for this part' to edit it Actual results: The text in the inner contenteditable=true region can not be edited, or deleted with the backspace or delete buttons, even when selected. Expected results: The contents of the region should be editable. This used to work without a problem in previous Firefox versions up to 38.0.5

This is HUGE regression in ContentEditable behaviour. Having ce=false areas inside ce=true is crucial to many features in rich text editors. This completely breaks table editing in Wikipedia's VisualEditor, and the 'Widgets' feature in CKEditor.

Duplicate of Bug 1181130 despite this having the lower number.