I will describe what I did, but is it possible to post up a 440KB .cwp file, for somebody to check out? I have had this happen before and I have no idea why. Maybe someone can just nail it
 
The file has 3 synths. The first two were but when I inserted a 4th, and asked to insert a MIDI track into its folder, every time I try to Solo the 3rd synth's tracks, it solos the 1st one as well, or partially. If I then try to remove the Solo from the 1st folder, it un-solos the 3rd one....and so on.
 
This happened even after I deleted the sforzando synth and all its associated tracks and then reinserted them. It's when I insert the MIDI track into the 3rd folder that it all starts.
 
Just before that I tried to copy some notes from the 2nd folder's MIDI track, by lassoing and edit/copy, so I could paste them into the 3rd folder's MIDI track, but the paste would not come up because the events were refusing to copy. That seemed to resolve but is now back.
 
Now it seems that _any_ new MIDI track that I insert becomes linked to the 1st track
 
I am not being snotty, but unless what I have is germane to my problem, my probably dreadful structure is because I am just throwing stuff together to see what I can and cannot do with soundfonts etc. I am confused enough already.
 
Thanks for any help.
 

So I started a completely new project. From blank. It still does it. The last synth I install, when I give it a MIDI track in its folder, will affect the MIDI track of the 1st folder every time, if I solo it. The last MIDI track, even if I just insert it outside of any folders, will tie up with the MIDI track of the first folder.
 
If I create exactly the same structure by _not_ checking the create folder option when inserting a synth, then make a folder and place the synth and a MIDI track in there, the problem does not occur.

AHAH! I just realised that somehow the MIDI tracks were being pointed to the first synth, even though I asked them to be inserted into folder for the last synth. That seems a bit silly, but that was what trapped me.