I’m running the standalone editor, so my experiences might not address your questions, but I’ll try anyway (sorry for the noise). Also, my understanding could be way off, so don’t pretend this is authoritative.
The Preset Browser sends some sysex messages to the Sub 37 each time I select a different preset, so it is trying to keep the editor and Sub37 in sync.
Double clicking on an entry in the Hardware Presets column, does send a program change and some other messages. Since the Editor knows that the Hardware Presets column represents the internal memory of the Sub 37, it doesn’t have to send a preset sysex message to the hardware, and a program change will suffice.
So, is the LCD only for sending program change messages - like the hardware preset selector?
No. It selects which preset the other editor panels operate on, and it sends the preset to the “edit buffer” in the Sub 37, if needed, or a program change if the HW Presets column is active.
Where do the categories in the preset browser come from?
They are derived from the presets shown in the middle column, or from the presets in the right column, depending on which one was most recently used.
Double click a HW preset, and you’ll see the full selection of categories.
Make a new folder, copy a few HW presets into it, double click on one of those in the middle column, and you’ll find you have a shorter list in the Categories menu – these are the available categories in that shorter list of presets.
How do you change a category? Right click on the category field in the middle column, and see an option for that in the pop-up menu.
I have categories called User1 and User2.
Maybe I’m wrong, but I’ll guess that you’re on a Mac? If so, maybe try this: close the editor, remove or rename the “Library/Application Support/Moog Music Inc./Sub 37/PresetCategories.xml” file, and start up again. Was 0.9.42 installed over an older version? Something seems a little off.
… how the LCD display in the plug-in relate to the presets (hardware and librarian presets).
It simply shows the contents of the selected folder, or the hardware list. I find I need to double-click in the middle column (or the right column) to get it understand what I want to look at.
why don’t the hardware column to the right also show categories…?
Hmmmm, it’s more of a look inside the machine – a virtual representation of the banks and the slots within the banks. I can see how the categories might be useful there.
What I usually do, each time, is make a new folder called Backup, select all the HW presets (click one, and then Command-A), and then drag them over to the new folder. Now, when you look in the new Backup folder, you see the categories, and can sort by categories (something I find useful). That flexibility can’t be used in the Hardware Presets list, since it has a fixed Bank#-Preset# ordering.
I hope this helped!