I don't understand what you're asking ... all elements in my Detail windows retain the same layer information as the source elements. Are your source objects in the ArchiCAD layer?
In complex situations, it is best to copy the detail information a fixed distance to the right (or up/down/left) and modify the copy. After a rebuild, any updated geometry can be easily copy-dragged over to your working detail. The downsides of this include (a) manual process, (b) you might miss subtle changes, (c) you have to make sure that with two 'details' in the detail window, that you crop to the correct on in PM.
HTH,
Karl
One of the forum moderators
AC 28 USA and earlier • macOS Ventura 13.7, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB