Joerg, nice write-up. I posted that earlier but it was in the middle of your posting marathon so I deleted it.
I made some changes to readme based on your findings, and added a version of your .desktop file -- thanks for that. Besides the installer issue, can you see if that's all correct now?
https://github.com/AutoQuad/qgroundcont ... a1139869a5
(BTW, there was no carriage return in that apt-get line! )
Cheers,
-Max
PS. How do you spell your name officially? I assume with "ö" but you don't sign like that on the forums...