rectangle picking

http://www.blitzbasic.com/codearcs/codearcs.php?code=729

I found this but how do you program the "rect select tool", where you hold down the mousebutton and move it to expand a rectangle?

I cant do this with 2D commands because it would be too slow.
is this possible with Nsprite?

Yeah, simply create 4 white/other color sprites. And then scale them for the size of your lines and create your rectangle. If you can't get your head around it, I could create a small snippet.