I would make a new Event that turns off the Drag and Drop when the mouse touched the Walls ...you could even use an invisible helper sprite set to Mouse.x, Mouse.y position every tick....
The Helper Sprite "Buffers" the effect .and could even be dynamically scaled depending on where your mouse was on the screen, by using areas which affect scale..etc...you know..a dynamic real time..scaling of effect...IN the Military its called Scalar technology...if it works on a small level you just scale it up!!
What I mean is apply the Drag and drop disabling event to the invisible Sprite Helper..
so that it turns off well before the marble gets beyond the Walls..
So the Helper not the marble or the mouse triggers the Drag and drop disabling event..
Does that make sense?
Helpers are good for everything...
This is what I mean