Plugin editor - undo progam changes

Probably a stupid question but I still don’t get it.
When I change parameters of a plugin via MIDI CC or mouse the plugin stays in the altered state even if I switch to a different song with the same rack state (except restarting Cantabile that I won’t do every time). This seems to be VST specs.
I never understood why they don’t behave like hardware synths where you get the saved preset if you switch back and forth. There was a compare button on this synths too and you could compare the altered with the saved presets.
However, I like to reset the plugin to the saved state of the program everytime I swich songs or rack states.
I thought I could do it with the “undo programm changes” entry from the plugin editor and a binding “On UnLoad -> undo programm changes” in the rack but I didn’t find out how to use “undo program changes” with bindings.
Any help appreciated.

I had that issue also when I started using C3. I could be wrong, and hopefully more experienced users will chime in, but it could be your song states or the rack States. Probably the rack.
Double check that you’ve unlocked the State before changing parameters, make changes, Save All, lock it. If no luck, also check the State behaviors… Start with all parameters checked for testing.
However, I’ve occasionally had this issue even though all is set correctly… Usually on complex songs or when I’ve been editing songs for hours. A full reboot usually fixes it. But maybe that’s just me. Let us know how you make out.

No problem when preparing racks/songs. I do the unlock/lock states all the time.
I’m currently testing a MIDI controller for my drawbars and encountered that VB3II and B3-X behave different.
For instance, if you pull a drawbar out with VB3II and then switch to next rack state and back you see the drawbars in its initial state (before pulling out the drawbar).
With B3-X the drawbar stays pulled out if you switch back and forth. So if you use this rack state in a different song you have a problem.
When you edit a preset on a hardware synth and exit editing you are asked “save preset to” or “exit without saving”. AFAIK VSTs are always in edit mode.