vala-panel not visible "behind" Gnome's top tool bar

When launching vala-panel 0.5.0 inside a Gnome session (X11), get a flickering at the top of the screen (which looks like vala-panel coming up), but then I see Gnome's top menu bar again.

With this, I cannot even reconfigure vala-panel to appear at the bottom of the screen or such.

Maybe moving the vala-panel settings dialog into a separate executable and making it available in the desktop envs "Control Center" would be a way to work around this issue.

Other ideas / options to use vala-panel inside a Gnome session?

See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=894884 for the original report in Debian.

Greets, Mike