Bad rendering selecting a Compartment

In the ClassDiagram (and probably in all others diagram), we can get this result :

Step to reproduce:

1. Create a new ClassDiagram

2. Create 2 classes, Class1 and Class2

3. Move Class2 in other to get the previous display (Class1 behind Class2)

4. Select a Compartment from Class1

   The selected Compartment is displayed in front of Class2.

   We assume this is not the expected result. We think Class1 should be fully displayed in front of Class2 or fully behind Class2, but not with this strange display.

This bug also exists in Sirius-Web : https://github.com/eclipse-sirius/sirius-web/issues/4713