SUMMARY
The RGB parade scope is completely empty if Kdenlive is restarted.

STEPS TO REPRODUCE
1.  In an active project (with clips in the timeline) enable the RGB parade scope: View -> Scopes -> RGB Parade.
2. Verify that it shows something (move back and forth in your timeline and observe that the scope works).
3. Exit Kdenlive.
4. Start Kdenlive and choose a project to load.
5. After Kdenlive finished loading the project go to the RGB Parade widget. (It should still be enabled.)

OBSERVED RESULT
The window is just empty showing nothing.
To fix it, disable it in the menu (View -> Scopes -> RGB Parade) and enable it again. It will then just work fine again.

EXPECTED RESULT
The RGB diagram shall be shown.

SOFTWARE/OS VERSIONS
Operating System: Kubuntu 25.10
KDE Plasma Version: 6.4.5
KDE Frameworks Version: 6.17.0
Qt Version: 6.9.2
Kernel Version: 6.17.0-14-generic (64-bit)
Graphics Platform: Wayland

ADDITIONAL INFORMATION
It is tested with the latest app image and with my self-compiled version. Both behave in the same way.