Patch Assignments revert to default

I have 3 tracks in a song so far.  The first for Piano (channel 1).  2nd one Bass (channel 9).  And Drums (channel 10).
 
When I play it from the beginning it all works.  When I stop it somewhere along the way, the Bass track reverts to the Grand Piano default of the Keyboard (Kurzweil GS Studio).  If I start from the beginning it plays the assigned patches again. 
 
How can I keep the patch active for each track after I pause or stop the playback?  In the Console view, the patches remain as assigned and do not change.