Firefox download window empty

If you're like me and you're using download manager tweak you'll notice that it's not working anymore with the new version of firefox(firefox 26.0),and the developper of the plug-in is not availlable for consultation.
What you can do is downgrade to firefox 25.0b12 the last known working version; here's the link:

http://ftp.mozilla.org/pub/mozilla.org/firefox/releases/25.0b12/win32/

Ps: before installing firefox 25 backup your profile:
https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

Enjoy!