I have just upgraded firefox to 115.3, and now the menu and tab area have an ugly blue color with white text. If I switch to another window, the color returns to gray with black text, but as soon as I select the window, the menu/tab area becomes blue again. Only the active tab is shown with a gray background. I have found this bug (https://support.mozilla.org/en-US/questions/1090432) from 8 years ago, which seems to be the same problem, but the fix described does not work: In about:config, '''browser.tabs.drawInTitlebar''' is set to 0 (not true or false). If I set it to something else and back to 0, the blue color remains. If the value is not 0, one could argue that firefox should use the title bar color, but if it is 0, then the regular window color should be used. Also, regardless of which color ought to be used, the tab header is not connected to the window below, but separated using a blue separator, making the window exceptionally ugly. This is the case even when browser.tabs.drawInTitlebar is nonzero. I have also created a 100% fresh profile, without addons etc, and the behavior is the same.