User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:2.0b8pre) Gecko/20101011 Firefox/4.0b8pre Build Identifier: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:2.0b8pre) Gecko/20101011 Firefox/4.0b8pre When installing AdBlock Plus in Firefox 4.0b8pre, the extension's button causes the navigation buttons to become stretched vertically. Reproducible: Always Steps to Reproduce: 1.Download AdBlock Plus from http://adblockplus.org/ 2.Install the add-on. 3.See how the toolbar becomes stretched. Actual Results: The navigation buttons become stretched vertically in the toolbar. Expected Results: They should remain in the same proportions.

It did the same thing for me in Firefox 4.0 RC. All the icons of the navigation bar become stretched vertically when you install an add-on which puts an icon in the navbar. To fix this problem temporarily (until you install another add-on), I go in customize toolbar and I check and uncheck "small icons".

This bug occurs too in Firefox 4.0 FINAL. I added an add-on button (Scrapbook) to my navigation toolbar. And IT IS CONFIRMED whenever i double click the bookmark(the yellow star) button on any page on a website, the buttons on my navigation toolbar become streched. This only occurs when an add-on button is added side by side with navigation buttons. The only solution for me to disable the streched buttons is to close firefox or like above user, check and uncheck "small icons"

Can you attach a screenshot of the issue?

http://lulzimg.com/i18/7962b2.png http://lulzimg.com/i18/7285e8.png Here are the screenshots, notice on the 2nd picture, the buttons are streched. it only occurs when an add-on button is added side by side with navigation buttons.