> Yes.   I now see the checkbox on RX 5 in "save" but my mouse can't activate it.  Any idea why it sits there tempting me but denying me its use?

It looks to me that if you have opened in RX a file that hasn't any 
non-audio data,
the "preserve non-audio data" is not available.

If you open a file that has non-audio data, for example track marks, the
selection is available, and as a matter of fact there is a tic as default.

Eero