How to modify the Z order in Rational Rhapsody diagrams

Answer

Model elements are drawn in the "Z Order" that ensures a child element is kept in front of its parent element. So a class should be drawn in front of the package it belongs to:



The same class will be drawn behind another element that is not its parent:




However, where an appropriate parent-child relationship can exist, the model structure can be changed by dragging the parent element so that it completely encompasses the child element (or vice versa)
For example, the parent package of the child class can be changed simply by the way the elements are dragged onto a diagram:


Caution: should be used so that the user does not inadvertently change the model structure.

So the model dictates the Z order of the elements in a diagram but the model can also reflect the way in which elements are drawn in the diagram.

Free shapes and Notes, which do not follow or affect model structure allow modification of their "Z Order" by right clicking the shape/note and selecting either "Send To Back" or "Bring to Front".