I do remember there was a discussion about it but I was not able to dig up.
Detail Marker and worksheet came around AC10 (?)
Now we are at 20 and still it is recognized by the magnet. If there is a zone stamp under it or slab it is very hard to select the other object, you have to Tab cycle through the elements.
Please make Detail Marker / Worksheet marker empty inside and only selectable with polyline and marker head.