Input focus lost when switching back to vivaldi window
This is an effect which I have experienced with different window managers (in my case: fvwm and wmaker). I switch workspace or use alt-tab to switch between applications. When the vivaldi window has the focus again it does not take any input, i.e. shortcuts like 'Ctrl-t' for adding a tab, or even input focus in a form like this very one I am using for writing this message do not work. I have to click into the content area to get input focus back. The funny thing is, when I start vivaldi it works for a while. Once the problem has appeared it persists.