Here's a list of bugs I've found:
- png attachments are disabled (why? this is the most effective format for GUI screenshots!)
- insert image tool states png's are alowed, though, if you upload one it states it's invalid
- file open dialog shows only filetype availible as "All Files", but that's wrong. It should be named "all allowed filetypes", since "All Files" is commonly used for un-filtered view.
- file open dialog has "save" button instead of "open"