Draw a box on mouseDown

Back with a new project!

My boss woud like me to achieve this somehow. I’ve seen it done but have very little knowledge of HOW it’s done.

In a nutshell I’d like to be able to use the mouse to draw a box. But not draw the four sides. Instead, you could click and start dragging the mouse and a box would be drawn and grow as you drag. When you let go the box is there. But if you click and drag again somewhere else the first box disappears and the process starts over in the new mouse click position.

On the other hand, would it be better/easier/less processer intensive to just have a teeny box in a movie clip already on the screen and then have that change scale as the user clicks and drags?

Eventually this functionality would be built into a map. The map would be made up of tiles of a certain resolution. The box drawing comes in as a zoom tool. The user could click on the map, drag the mouse and draw a box. That would be the area they wanted to zoom in to. So I’m guessing I would use hitTest to find out which tiles the user drew the box on and then load higher resolution tiles.

But for now I just need to know how to get the box functionality!

What do you all think? Is one method better than the other?