LMSS not opens with icon after upgradeo to F39. While starting it from terminal it works

After upgrade to F39 my LMMS not started anymore. If I click on the icon it just opens quickly the LMMS emblem and disappears straight away again.

When I open it in the Terminal I can open it. I do get the message:
QSocketNotifier: Can only be used with threads started with QThread

I am not sure if this is important.

Please let me know if I should test something else.