Ok This is it...

[Condition]
Mouse pointer is over (Object A)
+ Repeat while left mouse key is pressed

[event]
Set X position (Object A) to X mouse position
Set Y position (Object A) to Y mouse position

And thats all.

There is one thing wrong though. It's, If you move the mouse too fast while your dragging the object, It way not be able to ceep up and the mouse will no longer be over lapping the object resulting in the dropping of... your presious Object...

tell me what think.