PDF not shown in Frescobaldi

[Noeck]

Hi,

when I compile a file with Frescobaldi, lilypond is invoked and creates
a PDF in the same folder as it should. But Frescobaldi does not show it.
When I go to Tools > Directories > Open current folder, I can open the
PDF there. It worked correctly with Frescobaldi 3.0.0 from the package repo.

Frescobaldi 3.1.2 downloaded from https://frescobaldi.org
(not installed via package manager on Linux)
I run it with this command:

python3 ~/frescobaldi-3.1.2/frescobaldi

Do you have any idea where the music view is gone?

Cheers,
Joram