https://www.geogebra.org/m/PHtUWdJ8 Look at the example ... you need to activate the 3D view to see the toolbar.
You can uncheck "Selection Allowed" to disallow deleting
The problem is that the two lists that are accidently deleted are thought to give a grid in the y-z-plane to draw a polygon on it. If they are not selectable it does not work.
I tried the same with the "normal" grid in the x-y-plane. That can be used of cause too, but ...
1.) if I want to let the object rotate to show it from every side to direction of the rotation is not really good
2.) I don't know a possibility to make the grid in the 3D view invisible while rotating.
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