Cannot remove the last/only material of a model

Steps to reproduce:

• Create/open a 3D project
• Select cubeModel in Navigator
• Open Properties view
• In Model -> Materials click x beside defaultMaterial to remove it
• -> field is cleared, but model in 3D view is still visible and Code view shows that material is not removed, see attached picture
• If model has multiple materials, deleting all except the last seems to work.