I finally tracked down my problem, but need a solution.
Having several “in-place-editors” (tested with velocity, or CC data) open in the main window, all the other editors, including making edits in the in-place-editors and moving between notes in the score window for example (even hitting undo on the keyboard has a lag), are all slowed down significantly.
The more in-place-editors open at once, is proportionate to the level of lag/slowness. I’m not sure but, it may be correlated to a switch from Windows 10 to 11.
Is there any way to solve the underlying problem?