Undo not working in an old track

Hi
I remember this happening from years ago - loading old tracks and undo not doing anything.

What is the checklist of things I need to go through to resolve this?

Thanks
midierror

I managed to resolve it, but I’m not sure what did it.

Possibly an old plugin.

¯_(ツ)_/¯

I’m having the same issue. But how could that be related to a plugin? (In my case I do have some ancient vsti from almost a decade ago or so, so that makes sense)
It’s weird right?

Yes, it is. But in view of the fact that you can’t change it, there’s only one option left: Take it as it is.
I had the same issue while creating my second last track, and I also don’t know what causes this. It has to be a plugin for whatever reason. And I don’t use masses of plugins anymore, I dumped about 95% of all my plugins. The ones I use are well chosen and have quality, many options and possibilities. And I use them over and over, so I’m not assuming that this effect is caused by a specific plugin in general. Maybe it’s caused by a specific setting in terms of that plugin which Renoise doesn’t like for whatsoever.

I was about to file a bugreport, untal I saw this one:

So we can blame synthedit. If you boil it down it should still work, but synthedit is dirty old code from waaay back. Nowhere near 2021 standards. So it is an vsti-related issue. Still a bit annoying though: I tend to rely heavily on undo.