I have tried to create a bounded box on my desktop PC today. Usually I’d just take a picture of one long bar and then rotate it to produce whatever boundary shape I need - but the rotation is done with a two-finger gesture. On the desktop, with only the mouse, I tested all usual combinations (left button, right button, with Ctrl, Alt and Shift) and none resulted in a rotation (I did discover though that movement and scaling have keyboard shortcuts, nice 
). I noticed though that the alignment feature (which shows red lines when it does something) will sometimes rotate my object, and then I have no way of cancelling that either. So how do I rotate something without a touchscreen?
Shift + mouse wheel should rotate the object rotation. Would you like to also have a keyboard shortcut?
I just created a post listing keyboard shortcuts.
Dear Henger,
It is now possible to precisely rotate and scale objects when dragging them by pressing Ctrl and Shift.
enjoy!