If Amarok window is shown in all desktops, and desktop is switched, the spectrum analyser stops updating. The only way to restore it is to minimize & restore Amarok window. If this is done in one desktop, spectrum analyser works in that window. Switching to another desktop makes it stop again.

Reproducible: Always

Steps to Reproduce:
1. Play a track in Amarok with spectrum analyser ON
2. Move Amarok window to 'all desktops' (right-click window title or click the 'pin' button on the title bar, if you have one)
3. Note that spectrum analyser keeps working as usual
4. Switch to another virtual desktop
5. Observe that the spectrum analyser is not updating
6. Switch to any virtual desktop and the observations remains
7. On one desktop, minimise & restore Amarok window and see spectrum analyser working fine