Animate Preview automatically updates the layout preview whenever you run "Check and Save" inside the schematic editor.
The preview displayed in the Animate Preview assistant window will turn gray to show that it is being updated and is currently out of date. If the enlarged preview window is open that will also turn gray.
N.B. you can not cross-probe while the update is running.
Once the update is completed, the new layout preview will be displayed in the Animate Preview assistant window, and in the enlarged preview window, (if open).