No, that is only called when no mouse buttons are pressed.
I'm mouse-dragging object A over object B.
A.MouseDrag() is called with over_object == B.
Nothing seems to be called for B.
This is a problem, because I need params for a mouse event over B.
Actually, I'm trying to drag one object by activating mouse-tracking on mousedown or mousedrag. Unfortunately, although "mouse tracker" appears in the status bar, there's nothing called for it that I can use for mouse_tracker.update().