AI_FMS command
Switches from paper space to model space.

Description
While in model space, it switches to paper space to the last used Layout and activates the viewport.
While in paper space, it activates the last deactivated viewport.
Switches from paper space to model space.
While in model space, it switches to paper space to the last used Layout and activates the viewport.
While in paper space, it activates the last deactivated viewport.