[xmonad] How to use virtual/on-screen keyboard in Xmonad

[Jakob Schöttl]

Hello,

I would like to use Xmonad to set up a custom, very restricted desktop 
environment on a Raspberry Pi with a touch screen.

Because there is no hardware keyboard I need a virtual keyboard. I tried 
these programs: xvkbd, matchbox-keyboard, onboard, florence

Some of them work with some other programs. But when it works, it's 
still buggy:

- after typing I have to click two times to a new input field to set focus
- virtual keyboard steals focus
- other windows get invisible and only come back when they get focus 
(super+j)
- doesn't work at all with some programs

Is there a way to get virtual keyboards work with Xmonad, reliably and 
for all programs?

Thank you!

Jakob