I don't understand exactly what you mean.  Do you mean that when you click on the "Place marker" icon in the "Right Mouse" toolbar, then try to place a marker it does not place a marker?  First I would try this without virtual reality, just using the mouse.  That is working for me in ChimeraX from a few days ago, but I see in today's daily build it gives an error.  Are you seeing an error, or just no marker is placed?  First I would try it with mouse, then try VR.  Unfortunately the VR marker placement does not have a mode to place the marker exactly at the 3d position of the want (cone tip).  That would be useful and I've been wanting to add that.  So in VR it behaves just like with the mouse only it places the marker along the line extending from the wand (cone).

Tom