Hi everyone, The problem is that in Firefox 79 for Linux, there is is a small margin between the close button and the upper right corner of the screen, that prevents me from clicking the close button when I put the mouse pointer at this corner (at the end of the screen). Because of habit and also because all other windows let me click the close button like this, I would like to ask if there is an option or a particular about:config entry in order to eliminate this margin, so that the clickable area of the close button expands to the upper right corner (end border of the screen) and regain the functionality that I have with all other windows. A long time ago I had again this question for a previous firefox version: https://support.mozilla.org/en-US/questions/1251999 I had fixed this problem with the solution provided in the answer of that question back then. Unfortunately, this fix with userChrome.css doesn't work anymore. Is there a way to fix this in firefox 79 for linux ?