Perhaps you could compress a simple problem project file (no samples needed) into a ZIP file and post it here as an attachment so we can have a look at it and see what's (not) happening? ... include your reaper.ini file in the .zip too.
-------------------------- Mike Rieger SCR Performance 970-214-9702 - Mobile
here we go, the testfile and the reaper ini, see attachment. for explanation: i`ve made that mini snippet of bladerunner main titles on request on kvr, it`s all done in hypersonic2 (so it would be of course best if you have hs2 ;) ). hypersonic 2 is set up so that every of the 16 parts of it are treated as if they were single vsti`s, they all have their own independant channels. i did that via feedback routing, so this has to be "on". i really hope you are able to give me a solution, as i for god`s sake dn`t find one ... :(
Got it, I think. When a track is selected the previously-selected track (which was recording) is disarmed for Recording. This causes an All Notes Off MIDI message to be sent out on every track. I tried disabling "Send all-notes-off when un-record arming a track" in Preferences >> Media >> MIDI but that did not work. There are osme other preferences on Preferences >> Audio >> MIDI devices too. It works Ok in v2.58 and in v3.00 ! (that first Preference is not in those versions)