The past couple of times I have tried to edit a post have been unsuccessful. The edit window opens without any of the post's text. Typing in the window isn't possible. Unless the font color is changing to match the background. This has happened on a Vista and a windows 7 machine in Firefox.
Same here on Firefox, it started two weeks ago today. IE still edits OK, but I don't use it for anything FF can do. I hadn't noticed the 'More Options' button either, it appears to solve the problem.