A stack "file selector" is already in memory

[Reinhold Venzl-Schubert]

Hi!

I opened a metacard-stack xyz in Revolution and got this feedback:

A stack "file selector" in file /Applications/Revolution Studio/2.7.4- 
gm-1/Toolset/revlibrary.rev is already in memory. The Revolution UI  
does not distinguish stacks which have identical names, so editing  
these stack files while both are in memory could result in data loss.

I deleted the substack file selector of my stack xyz and saved it,  
but after restarting I got the same feedback.
Before I opened the metacard-stack in Rev I tried to remove of  
ressources, but may be I have forgotten to remove the file selector.

What can I do to delete the substack file selector finally?

Thanks
Reinhold