Masking Problem

So I noticed this a little while back, but just assumed there was another way to achieve it but now I'm not so sure. I think prior to the overhaul of masking with all the shapes and what not I used to be able to create a square mask. Then I could hold ctrl+shift and I would be able to extend one side without affecting the others. This was tremendously useful when it came to creating things like a gauge that was filling or depleting. Now this seems to be impossible, they changes the hot keys but I think removed the ability to do this. Am I wrong, please tell me I'm wrong.