VW2016 Referenced symbol edit - information disappears

[JonCrossley 0]

We have a series of files with symbols of flat layouts that reference through to a series of other drawings that contain general arrangement information.  I am editing the referenced symbols in the top level plans and turning classes off that should not be visible.  The process of doing this seems to have actually removed the information from the symbol in the source file.   Is this a known problem?  How can I avoid it?  

 

Thanks!

Edited October 20, 2016 by JonCrossley