In the past when I Imported X_T or STEP they were divorced from the saved imported .SLDPRT file. The SLDPRT file was  NOT linked after import to the original X_T or STEP file.  I just had some imported surfaces in the .SLDPRT file ( A true DUMB solid)

But now it is not like that There seems to be a reference in the feature tree to the Original X_T file.

How do I get them totally divorced?