if the user click in an image which is zoomed in, than he can hold the mouse button pressed and move the image until mouse run against the display border. If he need more movement, he need to release the mouse button and start the process again.
From Rhino3D I know it that if the mouse leave the display (for example at the left side) than the mouse pointer come back at the other side of the screen (in the example at the right side). So, a large image can continuous moved by moving the mouse on the desk “without” limit. It could be a great enhancement and I like it a lot at Rhino3D.
Please let me know if explained it not right and I will try it better.