Forget it, if there's an (almost) invisible window (e.g. 1x1 pixel window size), one has to figure out which it might be and kill it in the tty console with `kill` (or `pkill` if you want), then a terminal can be opened with <kbd>Ctrl</kbd>+<kbd>Alt</kbd>+<kbd>t</kbd>.
Forget it, if there's an (almost) invisible window (e.g. 1x1 pixel window size), one has to figure out which it might be and kill it in the tty console with `kill` (or `pkill` if you want), then a terminal can be opened with <kbd>Ctrl< /kbd>+< kbd>Alt< /kbd>+< kbd>t</ kbd>.