Bug 333369

The crop tool is awesome, especially the grow function, but I'd like to have this feature that seems to me logical.
If you have width/height constant, you cannot change the cropping rectangle size by the handles, of course, but if you move the rectangle near the borders of image, just to be sure to cut well, and you go on moving the rectangle against them, the rectangle change size!
Well, I'd like to have a fixed cropping rectangle size as set numerically in every situation.
Thank you in advance.

Reproducible: Always

Steps to Reproduce:
1.Insert numerical values in crop tool options field for width/height
2.Turn on constant for width and/or height
3.Move cropping rectangle against image borders
Actual Results:  
The cropping rectangle changes size despite the locked width/height values in the tool options

Expected Results:  
The cropping rectangle should have the same size set in the width/height values in the tool options

I'm not sure if it's a bug, but I'd like you solve it/add this feature.
Thank you