Ubuntu / XWindow bug? Lags when mixxx window out of visible area

[Wihola IT]

I recorded the video, what's going on. There is no sound but picture is pretty self explanatory. I doubt it's a mixxx bug. Anyone else experienced that?
http://stunkit.com/data/files/2017-03-23.flv
Ubuntu 16.04 x64
Mixxx 2.0.1 alpha pre

It happens if waveform is under the launcher. Need to move out of view area more than 50% of the window.

[Daniel Schürmann (daschuer)]

Thank you for reporting the bug.Unfortunately the video is not that self explanatory because I cannot see when you click and when the lag happens.

Please explain in words What did you do, what did you expect and what did Mixxx instead?

[Wihola IT (wihola)]

I click all the time only one button Play. Look at the waveform when the window moved aside. It looks and feels like mixxx FPS drastically fall down. But mouse cursor speed is o.k.

[Be (be.ing)]

I have noticed this too. I presume it has something to do with how X and/or Qt handle OpenGL widgets that are off screen.

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/8836

[Daniel Schürmann (daschuer)]

This old bug seems to be finally fixed with 2.4-alpha. @wihola, can you confirm it?