Shuy, I made a modified version of your Shell1.pp2, which I have named "Shell1A.pp2". I changed the names as I suggested in a previous post, namely:

Mag Base Lt_1
Mag Lt_1
Mag Zone Lt_1

Mag Base Rt_1
Mag Rt_1
Mag Zone Rt_1

Shell_1

For me in P6, the magnets load with the original names that I gave them, even when there were other magnets in the scene, and if I save the Shell_1 back to the library, the magnets still retain the original names I gave them. If I delete the Shell_1 and magnets, then load the Shell1A.pp2 again, the magnets still retain their original names.

I have attached the modified version of the file above. To attach it to this post I had to add a ".TXT" file extension, you will need to remove that before you can use the file.

Quote - If I delete prop scene is empty - there is no magnets nor props, but if I load prop with magnets again magnets names are changed and visible as a dials in prop window.

Remember your magnets are hidden from the menus. If you delete the Shell, the magnets will still be there in the scene. You have to delete the magnets as well as the Shell. If magnets are attached to a figure, deleting the figure will also delete the magnets, but it works differently for a prop. If magnets are attached to a prop, you need to delete both the prop and the magnets. As the magnets are hidden, you will need to use the Hierarchy Editor to select them.