Firefox 4.0 Navigation Bar icons become stretched (vertically) when adding a bookmark. The problem appears to do with the WOT (Web of Trust) or Adblock Plus add-on and when their respective icons are present on the Navigation Bar. Selecting the bookmark function, either from the menu or the favourites star icon, results in the bookmarks pop-up appearing just under the yellow favourites star, it's at this point the stretching occurs. If I remove the icons of the two add-ons mentioned above, using the "customise" function, the Navigation Bar and any remaining icons revert back to their normal aspect ratio. If I in turn add the offending icons back on, again using the "customise" function, the bar stretches again, note that I have not exited Firefox at any point. The only other way to reset the size of the icons, without removing any icons, is to restart Firefox. This is a repeatable problem, if I have the offending icons on the Navigation Bar and I use the bookmark's function, the icons will become stretched. I do have other add-ons, but they do not cause any problem with the aspect ratio of the Navigation Bar. I have also noticed that when a pop-up appears for when Firefox is asking about saving passwords, similar to the bookmarks pop-up, that this does not cause any problems with stretched icons, even with the at issue add-on icons present. So is this a problem with Firefox 4.0 or something to do with the icons provided by the add-ons developer?