The Rich Text Editor (Midas) on an iframe stops working if the element that contains the iframe is hidden and shown again. From what I can see, the presshell gets killed and the editor gets screwed. I'll attach a test case.
Created attachment 140091 [details] Test case This test case is modified from the original (http://www.mozilla.org/editor/midasdemo/) Rich Text Edit Demo. I've added two links to the bottom, Hide and Show. To see the problem, try the editor (works), click hide, click show and try the editor again (can't edit, no caret).
Whoops, I should've found the earlier bug about this. *** This bug has been marked as a duplicate of 217205 ***