I can't get the markup buttons to work correctly with Firefox. I highlight the text and hit the button, but the tags show up after the selected text. Kind of like when you try to markup an edited post and it screws up.
I'm aware of the issue, it's not new. The JS hooks for selecting text are amoung the least cross platform, so it works in IE, and in Firefox/mozilla it was all I could do to make it insert tags and not shoot up error messages.