Overlapped, non-child DropAreas don't receive events

The dropAreas seems that have problems with the enter and exit events if this areas are overlapped.
In the attached example you can drop the yellow rectangle to the three dropArea represented with a red, green and blue rectangles. The green area is child of the red area and receives the enter and exit events perfectly, but the blue area don't receive any event if you enter in the red area before.