Thanks! This all makes sense now, and I would guess that it is the same issue with Samplitude. And since it is an IEditController function call, then it is a developer mistake with the VST3 hosting and not with VSTGUI4 - this also makes sense because I’ve been using VSTGUI4 in all sorts of non VST3 plugins and standalone app interfaces for years and have never had any problems like this. So while it means more work for devs to correct this, I am relieved that it is not on the plugin side.
- Will