To do this, choose Customize from the Control panel menu. You can turn controls in the Control panel off or on to make it more to your liking. If Never is on, dragging an image moves only the frame, and then image is moved when you release the mouse button. Do you want the image to redraw when you move an image? If Immediate is in, the image redraws while you drag. Determine the balance between performance and visual quality when you scroll through a document, which causes text and images to be greeked. When this option is on, you can dock floating document windows (just as you would dock panels).
