When you click the Player Mode button below the Canvas, the Canvas expands to fill the Motion workspace. This is helpful for watching project playback without the distraction of the software interface. In this mode, the menus, toolbar, and timing display remain active. The Show/Hide Timeline, Show/Hide Audio Timeline, and Show/Hide Keyframe Editor buttons at the lower-right corner of the workspace also remain available, as does the Show/Hide File Browser/Library/Inspector button at the lower-left corner of the workspace.
Do one of the following:
Choose Window > Player Mode.
Click the Player Mode button above the toolbar.

Press F8.
Do one of the following:
Choose Window > Player Mode again.
Click the Player Mode button again.
Press F8 again.