ok ok, found the solution here:http://katapult.kde.org/handbook#Configuration_Dialog
If Katapult does not show up in the system tray, simply press Alt-Space. Once Katapult launches, then press Ctrl-C.
besides, with katapult you can also do calculations (enter for example 2.3+4.5), and you have a spell checker (Enter for example "spell organisation")... Very cool!