Simply use the 'Autodetect' button, or use app called 'xprop' : In a kvt run 'xprop', a cross should appear. Point to the window you want and click. Xprop will print all the window's properties, so look for WM_COMMAND, WM_NAME and WM_CLASS ( some of them may be missing ). If the property consists of several text strings, join them ( make a space betweem them ), e.g. for WM_CLASS(STRING) = "kvt", "kvt" enter 'kvt kvt'.