In reply to your email:
If you have a careful look at your mouse-cursor (or pointer) after you enable the Crop-Tool, if you hover the cursor over the image it will have a type of scissor icon. If you move the mouse-cursor to the very edge of the image the icon will change to a two-way arrow pointing in the two directions you can stretch or shrink the crop area.

Important thing is try not to press down and drag until the icon changes to the arrow. In other words, do not press down on the mouse-cursor until you see the arrows! Hover the mouse-pointer over the image until you see the arrow icon, then press down and move. Do not press down on the mouse until the icon changes to the arrow icon.
Also keep in mind the dotted area surrounding the image is the crop-area.

I'm unable to snapshot the actual mouse pointer icons.