Categories in the lv2 plugins are supported, some plugins use them, some don’t, it would really need to set by the upstream plugin developer.It’s been mentioned it before not implemented. Controller menus & presets in LV2 plugins - #2 by jofemodo
What’s needed is find out how many lv2 plugins have grouping already, submit an issue to GitHub - zynthian/zynthian-issue-tracking: Centralized Issue Tracking for Zynthian Project to enable control grouping for those plugins and then try and encourage the developers of the lv2’s that don’t do that to also add the functionality.
Probably a separate issue should be opened for the non-lv2 engines as the control list is pretty much mapped manually for those.
I also guess that ui could reflect a different encoder position but you’ve not considered the people who put their encoders at the top, at the side, in a diamond shape, three on the left and one underneath, two at the top, one massive one on the right and one on the base that you have to lift up the box to get at, only have one encoder and use a slider to change it’s hardware address, or whatever other frankly deranged layout @wyleu has set up this week.
edit: I’m sure someone will build a one-knob-per-function zynthian for zynaddsubfx eventually too.