Awesome add-on but v4+ screwed up my Firefox Rated 4 out of 5 stars

I used version 3.0 before and it worked fine, updated to 4 and now there is a strange bar at the bottom of my Firefox, below the status bar, I cannot get rid of it.

This review is for a previous version of the add-on (4.2.5.1-signed). 

Need more information for support

Hi,
Could you write an issue about this on the support site : http://code.google.com/p/scrollupfolder/issues/list ?
Please add your Firefox version, addon version, OS name and any detail that could help me to reproduce and fix your bug.
Thanks you !