This seems to be an issue deep inside UI drawing code. The nodes render
the panel button in the correct place,
but it doesn't correctly update the button state after a redraw, unless
the mouse is moved. The button is still in a `BUTTON_STATE_HIGHLIGHT`
state after drawing, and a mouse press will trigger it regardless of
where the mouse cursor actually is.
A common hack to force a reset of the button state is to add a fake
mouse move event using `WM_event_add_mousemove`.
Pull Request: https://projects.blender.org/blender/blender/pulls/112503
fdf1040532