Two Ways of Z Ordering is Confusing

A user was confused as to how to do Z order and to be honest I had to play with the GUI a bit to see what it was doing, because I did not expect the context menu under Stack to have both a Z modifier mixed with ordering in the scene graph. 

Raise/Lower affect navigator order.

"To Front"/"To Back" affect z value.

At first the user thought changing the Z property was the only way. Then they were confused as to why moving the order in the navigator (scene graph) order did not adjust the Z property.

This was only one use but I bet many who aren't familiar with QML or scene graphs will be confused about that as well as "To Front"/"To Back"using z instead of sibling order.