Can't rezise task boxes and can't move arrows

I have an issue with resizing task boxes and moving arrows (other starting point from task boxes). When I click on the box I only get the pointing hand cursor and not the cursor with two arrows for resizing. If I click on a arrow I'm unable to move the starting or end point. I did uninstall the Bizagi and installed the newest version, but the issues still remain.

I have it in a new model as well and opened a lot of other models as well with the same result, so it is not model related issue. I can move the elements but only with the arrow keys not with the mouse.

My operating system is Windows 7 64bit.

Thanks in advance for your reaction