In textbox, when there are lines wrapped, then edit a while and some warpped text will overlapped and blink. steps to reproduce: 1. new a bookmark. 2. in the "New Bookmark" dialog, paste following 2 lines in "Description" field Portions of this content are ©1998–2013 by individual mozilla.org contributors. Portions of this content are ©1998–2013 by individual mozilla.org contributors. 3. move caret to the beginning (before the first 'P' letter), press enter to produce a new line, press backspace to delete the new line, and enter + backspace again. 4. text overlapped, see the attached pic This can be reproduced in any textbox, make sure that text lines are wrapped, and caret is visible. I hit this bug when edit note in the Scrapbook addon. often the overlapped text also blink. the last good nightly seems to be the 20130912 build.

Dupe of bug 916751?

This should be fixed in the next Nightly. Please check and re-open the bug if not.