Small gap appears in Firefox main window after first use of globalmenu

[Carlo Cannas]

To reproduce:

1. Start Firefox on Unity
2. Open any menu from the globalmenu (e.g. File) of main window
3. Notice that the toolbars have moved 2px below their original position (see attachment)

This seems to happen only on the main window, other windows such as the Scratchpad window don't show the problem.

I added to my userChrome.css the following piece of code:

window[shellshowingmenubar="true"] toolbar[type="menubar"]:not([customizing="true"]){
 height: 0 !important;
}

That solved the problem for me, and so far I didn't found anything broken by that CSS rule. So it should be enough to put it in xul.css by unity-menubar.patch.

[Cavia Porcellus (caviaporcellus)]

This is still a problem in Firefox 44 on a stock install of 15.10. When Unity's menu bar is opened, Firefox's menu bar is opened as well, but it only shows up as a two pixel-tall line. If you go to the customize screen the thin line is visible there; you can even add icons and whatnot to it.

This probably hasn't gotten the attention it deserves because older Firefox profiles may not be affected. Well, those two lines of pixels are lost but the tabs don't suddenly shift down so you don't notice that anything is wrong (I didn't realize the issue until I reset my Firefox profile). I'm not sure what version of Firefox changed this behavior.

Regardless, I can confirm Carol Cannas' fix works great.

[Cavia Porcellus (caviaporcellus)]

This same issue also affects Thunderbird. Carol Cannas' fix works for that as well.