When you add a surface (flat image, bilinear, or bicubic) or geometry (3D text or model), the surface or geometry appears in front of all other objects in the scene. These overlapping objects create a stack and an order of priority as one object is drawn in front of the other.
You can change the drawing order of surfaces, 3D models, and other objects using the Priority Editor.
Each entry in the Priority Editor indicates the object's name, the order of the object in the stack, and the location of the object in its branch. There is also a proxy showing what the object looks like in Schematic view.
To access the Priority Editor, click the Priority button, or swipe the bar at the bottom of the Media or Object menu.

(a) Drawing order of objects in the scene (b) Priority Editor controls
Use the Priority Editor controls to analyse the scene for changes in rendering priority, to change the rendering priority, and to cut, copy, and paste priority information from one frame to another.