User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:2.0b11pre) Gecko/20110126 Firefox/4.0b11pre Build Identifier: Mozilla/5.0 (Windows NT 6.1; rv:2.0b11pre) Gecko/20110126 Firefox/4.0b11pre When a Firefox window is maximized on a non-primary monitor, there is a thin white border on the bottom. This should not be there. When maximized, web content should be flush with the edges of the screen (as seen in all other browsers). Bug is most visible in webpages with dark background colors. Reproducible: Always Steps to Reproduce: 1. Maximize Firefox window on a secondary monitor (preferably with a website with a dark background) 2. Notice thin white border on the bottom of the screen that prevents web content from being flush with screen edge. Actual Results: Thin white border on the bottom appears. Expected Results: Web content is flush with screen edges.

Note the black border on the bottom is just how Windows handles dual screens. My secondary monitor is smaller than my primary so it fills in with black.

i can see this bug using str from comment 0

I have this same problem... I have 2 monitors (the bug appears on both monitors), Windows Vista 32 Screenshot: http://i.imgur.com/bRJ48.jpg

Pretty sure this is fallout from bug 575245 adding a 1px margin at the bottom to stop taskbar auto-hide issues and failing to check if there actually is a taskbar on the current screen.

(In reply to comment #6) > Pretty sure this is fallout from bug 575245 adding a 1px margin at the > bottom to stop taskbar auto-hide issues and failing to check if there > actually is a taskbar on the current screen.

I am not sure it is possible, or if so if it is worth trying to figure out if there is a task bar on the current screen. But the margin is there on purpose so that auto-hiding the taskbar works correctly. Contrary to popular belief, you can have the taskbar on the non-primary monitor. There are also third party things you can install to make the taskbar stretch across both monitors. My personal opnion, is that all of this is really a Windows Display Manger bug. It should really be taking care of the taskbar auto-hide in a manner that does not require such convolutions on the part of every application that wants to not use the default window decoration.

Maybe we should be looking into how Chrome does this? I don't think Chrome is using the default window decoration either.

It still isn't fixed :(

Without that, auto-hiding the taskbar does not work correctly if you move the taskbar from the primary to the secondary monitor.

Well, I just have my taskbar at the top and I'm not using multiple monitors or the autohide feature.. Maybe it can be implemented differently? ie: only when the autohide option in Windows in enabled. Also, I see the line in IE, but not in Chrome..

If the line cannot be removed, why cannot it be black instead? That way it would not stand out so much. I believe at least 75% of the displays in the world have black borders. Is there some reason the line has to be 100% white?