Not sure if this is it, but I know while working in the Arrange Window/Project Window, that if you try to adjust, say the volume levels (from to your left area) as you have the selected/highlighted track (say EZDrummer VSTi drum track), the level change won’t stay, or won’t have any affect…but if you go to the mixer window view and adjust the level there, directly from the VSTi channel/track, the level change will stay put.