Aspect Ratio acting up

[keenart]

Problem.

I create a 9 pixel thick Outline of a square 200 pixels by 200 pixels, with the Aspect Ratio locked. As I look at the square, I decide I want to change to the dimensions to 220 by 220 pixels square.

I right click the mouse to bring op the Object Properties dialog box. I change the dimensions to 220 pixels, with or without the Aspect Ratio Locked, and when I click one pixel on either dimension, the size jumps to 241 pixels. Now frustrated, I set both settings to 220 pixels and click OK to save my changes. The square jumps, and when I open the Properties dialog box again, I find both dimensions have now changed to 239 pixels. No matter what I do, I cannot get the dimensions to remain at either 200 or 220 pixels square.

The above happens no matter what shape I draw.