[As 2.0] Width and Height Locked

Hi, i want to make 2d isometric cases into my map… The rules said : rotate 45 degrees, and modify the height of the case by itself/2…
The problem is that when I try to modify the height like that :


mc._height = mc.height/2;

It modify the width too, its like when the Height and the Width are locked in the object property…

I need help! fast please!
Thanks!