Tested with DS built wiht Qt 6.1

With Qt6.1 I should be able to add 2D content to a 3D scene, but 3D Editor breaks when doing so.

Steps to reproduce:

• Add Quick3D module to a project
• Drag and drop View3D component to Navigator
• Drag and drop e.g. rectangle from Default components to Cubemodel in Navigator
• -> 3D Editor looks as in attached picture
• Select the rectangle component by clicking it in Navigator
• -> selection shown weirdly on Form Editor, see attached picture