When hand drawing animation, it is very important to stay on model as it is easy to lose the proportions or features of a character. The Shift and Trace feature lets you temporarily move a drawing so you can trace it on a new drawing. This is similar to animators working on an animation light table and using an entire character or cut-out pieces of a character and moving it underneath the new drawing to trace it.
When using Shift and Trace, drawings are not permanently modified. They are temporarily moved, rotated or scaled to help you trace over them. Once you are done, you can turn off Shift and Trace to reset all drawings to their original position, angle and size.
If you use the Shift and Trace feature frequently, you can assign keyboard shortcuts for Shift and Trace routines in the Shortcuts tab of the Preferences dialog box