It has all manner of issues with wxWidgets event processing. The
primary one that Kicad stumbles over is that there is no kill-focus
when the mouse leaves the thumb if the sim is running, so subsequent
mouse-up events (even if in another window) generate thumb scrolls.
Another one that gets us is scroll events being generated when the
window is fronted, but this may be debugger-specific.
Fixes https://gitlab.com/kicad/code/kicad/issues/11366