App Bar is a UI component used with Bounding Box. Using the 'Adjust' button, you can turn on/off the Bounding Box interface for manipulating object.
Drag and drop AppBar prefab into the scene hierarchy. In the inspector panel of the AppBar, you will see Bounding Box under Target Bounding Box section. Assign any objects that has Bounding Box. Important: Target object's Bounding Box activation option should be 'Activate Manually'
