"onboard" keyboard shows the layout of the correct language but uses the wrong one

on antiX I need a on screen keyboard, I went with "onboard" and installed it. I also have multiple input languages set up in the antiX control center (German, Russian). Onboard seems to recognize it, because it shows me the layout of the correct language but as soon as I klick on a button it switches back to English and the character it puts in is actually also from the English layout. What can I do?