Objects have a certain order in each page.
The order is represented by the order in the project tree:
The bottom of a level in the project tree represents the foreground, the top represents the background.
Newly created objects are always put at the bottom of the project tree / in the foreground of the scene.
The Z-Order can be changed in several ways:
1.
By right-clicking the object in the project tree or in the scene and choosing the category Z-Order.
Then the object can be set
- one step to the front (Level Up)
- one step to the back (Level Down)
- into the background (Bring To Back)
- into the foreground (Bring To Front)
2.
By using the Level Down 
and Level Up 
buttons in the page editor.
3.
By dragging and dropping an object in the project tree.
The Z-Order in a page also influences the order that input objects are selected with the encoder.
There is a property called "Roll Over" that can be accessed with JavaScript. If set to true for input objects like Numeric Fields, turning the encoder beyond the absolute value limit will roll the value over to the absolute minimum value. For frames, it will switch from the "last" object on the page back to the first one.