Limited usefulness
I bought the app hoping that the full-screen crosshairs could just be left on and that normal interaction with my software would be possible. Unfortunately, this is not the case. When the crosshairs are invoked, you can perform a lasso measurement, then the mode is exited. I did contact the developer and am hoping this general cursor use can be implemented in a future version. (If that is the case, I will update my review and rating).
Bbba about Euclid, v1.3