Drag and drop using a target area on the movie clip

Hello,
I am a total newbie to AS, have been trying to teach myself, and it is tough going! So here is my problem:

I am trying to create an application for students to visualize their course schedules. I have rectangles representing each class, which students can drag and drop to build their schedule. I would like the students to be able to type in the course number and name before adding it to the schedule.

I have the drag-and-drop working, and editable text working. However, when I try to edit the text, it drags the box as well. Therefore, I would like to be able to limit the “drag” functionality to one corner of the rectangle. So the user would have to click that part in order to drag the movie clip. Please see the attached image to get a better idea of what I’m talking about.

Any help would be very much appreciated, thanks!
Chandra