When I use the Rectangle or Ellipse tool and hold shift, it doesn't give me an even square or circle, but instead scales it as a rectangle or oval. I can only make a perfect shape using grid and snap to grid but that's really not the right way. I also have a similiar problem with the Ramp effect-Radial ramp, it creates an ellipse instead of a circle.
Btw on Ai and Ps shift key works ok.
I'm using AE CS6 on Mac 10.8.5
What is the pixel aspect ratio of your composition? Do you have pixel aspect ratio correction turned on?
Changing the pixel aspect ratio in composition settings solved the problem. Thank you!
You have to make sure that you understand PAR. It is always best to work just in square pixels and reserve non-square pixels just for final delivery if that is specifially required by the outfit requesting the file.