Qsnap Crop tool not working?

Hi,

I've been looking for a tool just like qSnap for a long time now and I finally found it. But, the crop tool doesn't seem to work right.

I screen shot the photo with the tool, and then I select the crop tool.
I drag my mouse to create a rectangle around whatever it is I want, but it just stays that way. The tool allows me to adjust the dimensions of the rectangle but it doesn't single out the selected image. I will include an example. It remains the same no matter what I try and I was really hoping someone could help me understand what's wrong.

I'm really looking forward to using this app, but it is almost useless to me without the crop tool.