Droppable must have one element to drop on, otherwise I cannot drop

Droppable must have one element to drop on, otherwise I cannot drop

Hi,
 
I am using draggable and droppable in my application. Now I am using an UL for draggable and droppable. I have set some min height and min-width to both of them. Now in my droppable I have added a single line "Drop your records here" Now when I drag and drop an element I have to drop it exactly on the already written text. If i drop in the blank area below that the element does not gets added. How to do this? Please let me know if you did not get my question.
 
Regards,
Girish