User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:44.0) Gecko/20100101 Firefox/44.0 Build ID: 20160212012805 Steps to reproduce: Browsing Actual results: I love Firefox because its very open source and is one of the best browsers in the world. But I do not understand why the topmost tile bar in Firefox is constantly killing a particular amount of vertical height in my screen. I have posted an image that showcases this title bar in my second reply to this post. Please note this problem does not appear in Firefox for windows. They have solved this issue ( I sincerely hope it is fair to call this an issue). I understand that this is a small amount of vertical space but there are many times during a day even that little bit of lost vertical space really matters. I thank Firefox for making the windows version free of this issue and I would like to make this an opportunity to propose to the Linux development team to kindly consider this issue. The way I see it, that top most title bar does not serve a purpose. Usually the tab already contains the "title" of a webpage embedded. moreover chrome, opera too does not have this title bar although they used to have it.

Not a cocoa widgets issue (reporter is on Linux), bumping this to Firefox.

FYI, there's a workaround using the addon Hide Caption Title Bar Plus. I don't know if it's on by default, but there's an option to hide the Linux titlebar. It is best used with a theme, since the tab bar will be the same color as it normally is. I personally use Bright Blue by MaDonna. I will attach a screenshot. (Note, I also use the "smaller titlebar" option.)