The latest version of Firefox (I'm using 62.0.3) seems to have colonised certain keyboard shortcuts I use with other software and I can't find a way to disable them. The one that's causing problems is Cntl+Shift+w which Firefox uses to close the window but which I've been using with other software to open an overlay. Firefox support pages say you have to use a SAKA key add-on to customise shortcuts but that particular shortcut isn't among the ones that SAKA let's you alter. Firefox has always prided itself on being accessible and almost limitlessly customisable to the benefit of users. I am totally aghast at the idea that it is now imposing certain settings on users and not allowing them to be changed.