Easy to reproduce using the benchmark demo app from: https://git.qt.io/playground/benchmarkdemo

There are a few issues here:

• If initial msaaMode is NoAA, then toggling it at run-time does nothing.
• If initial msaaMode is X2 or X4, it can be toggled between NoAA and X2/X4. It does not actually change the mode to X2/X4 from the other one, but continues rendering. If changed to SSAA, it stops rendering.
• If initial msaaMode is SSAA, it can be toggled between NoAA and that one.