First of all, I think this extension is great.
Shortly after using this extension in Firefox 3.0.7/Vista, I noticed the following:
1) Go to any web page.
2) Right click on a blank area, choose "Bookmark This Page"
3) To the far right of the "Folder" area, click on the square with down arrow. It has the tooltip that says "Show all the bookmarks folders"
4) You'll notice all the folders here appear in BOLD, but they are not supposed to. If you repeat these steps with Firefox in safe-mode, you'll see they don't appear in bold.
I think I have found what is causing the bug. I looked through the source files for this extension, searching for "bold"
The bug is in passwdmaker.css, line 46
I changed line 46 to "font-weight: normal;" and the problem seems to be fixed.