Adding View3D to navigator is slow and sometimes impossible since detached navigator goes behind design studio window, see attachment. Steps to test:

• Create a project
• Add QtQuick3D import
• Detach navigator view
• Drag and drop View3D item from item library to navigator
• -> Stop/item not allowed to drop - icon is there for a long time not allowing to do the drop. Sometimes drop eventually succeeds but sometimes navigator view ends up disappearing behind Design Studio window.