1036856 - Redo deletes all Rich Text content on http://qa.moodle.net editor

Status: NEW

(Core :: DOM: Editor, defect, P5)

Description

[[SV Manager] Florin Mezei, QA (:FlorinMezei)]

Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Firefox/31.0
20140707160635
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:32.0) Gecko/20100101 Firefox/32.0
20140709004001
Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:33.0) Gecko/20100101 Firefox/33.0
20140709030201

Steps to reproduce:
1. Launch Firefox with a clean profile.
2. Go to http://qa.moodle.net/mod/forum/post.php?forum=2 and login (e.g. student/test).
2. Type the word 'Test' into the rich-text editor.
3. Alt+Tab twice to navigate away and then back to Firefox.
4. Type CTRL+Y (Redo).

Expected results:
Nothing happens as there's no action to Redo (or the last undone operation is re-done as expected).

Actual results:
The text is removed. From this point on, any text you write/paste/edit, when doing Ctrl+Y then all text in the field is deleted.

Notes: 
1. The issue has been there ever since the Rich Text Editing controls for qa.moodle.net started to show up in Firefox 15.0.1. On smaller versions, no rich text editing buttons display, so it's just plain text, and Ctrl+Z and Ctrl+Y work without any issues. This means that the issue is NOT a regression.
2. If you click "Show more buttons"->"HTML" then the editor switches to plain text and again there is NO issue with Ctrl+Z and Ctrl+Y.
3. I haven't seen this issue in other Rich Text editors, like the ones for Yahoo Mail or Gmail (Ctrl+Z and Ctrl+Y work without any issues there).

Comment 1

[Jens Stutte [:jstutte]]

Bulk-downgrade of unassigned, >=3 years untouched DOM/Storage bug's priority.

If you have reason to believe this is wrong, please write a comment and ni :jstutte.