When working with block selections, you can resize the area by dragging the handles on each of the four corners. However, I can't seem to find a way to resize the area by dragging a single side of the rectangle. If Acrobat lacks this feature, I will be surprised.
MS Paint vs Adobe Acrobat.
I am currently using Mouse Keys (
Control Panel\Ease of Access...) to move one axis at a time when dragging a corner. It works, but it is less than ideal.