User-Agent: Mozilla/5.0 (Windows; Windows NT 6.1; rv:2.0b3pre) Gecko/20100730 Minefield/4.0b3pre Build Identifier: Mozilla/5.0 (Windows; Windows NT 6.1; rv:2.0b3pre) Gecko/20100730 Minefield/4.0b3pre When I set larger text size in Windows 7 (125%), all buttons in Minefield get an additional 2px height. This also takes effect on "Back" button, which is vertically stretched and looks oval-shaped. It doesn't depend on Aero or D2D. The screenshot is magnified. To the left are buttons at 100%, to the right at 125%. Reproducible: Always Steps to Reproduce: 1. Set text to 125% of normal size (see how - http://windows.microsoft.com/en-us/windows7/Tips-for-making-Windows-easier-to-use#section_2 ). 2. After the log off start Minefield. Actual Results: Buttons get +2px height and "Back" button doesn't look round. Expected Results: Buttons should preserve their height. If it's not possible, at least "Back" button should remains round.

I’m experiencing this as well and I haven’t changed any settings of the text size in my Windows 7. The text size is set to 100% and I’ve recognised that the back button really is not round.

Karel Jára, in your case back button (and all others, just they are not round so it is harder to notice) is affected by some big icon of one of your addons. It makes Firefox to stretch all buttons to fit the height of that big icon. similar ticket https://bugzilla.mozilla.org/show_bug.cgi?id=583695 i have started my own https://bugzilla.mozilla.org/show_bug.cgi?id=644973

Yes. It’s true, this was solved for me some time ago when the add-on got updated.

Reproducible on Mozilla/5.0 (Windows NT 6.1; rv:2.0) Gecko/20100101 Firefox/4.0

In reply to Comment 5, the "back" button in firefox has an oval shape if changing the system's text size to 125% or 150%. It is unclear whether this is normal or not, because the original size of the "back" button is 32px by 30px (see bug 544999)

This bug should be fixed by the patch for bug 571454.