MOVING MULTIPLE CURVE POINTS AT ONCE

If you're working in the Curves dialog (Command-M [PC: Control-M]) and you want to make more than one point active at the same time, click on one point (to make it active) then hold the Shift key and click on another. As long as the Shift key is held down, you can click on as many points as you'd like to make them active at the same time.