I found a temporary solution: I installed the Logitech SetPoint drivers for my mouse, then programmed one of the buttons to simulate pressing the * key. That's the good news. The bad news is, I have to use Logitech's SetPoint drivers. I do still hope the expansion state of the Libraries will be remembered/enabled in a future build...
Hmmm, maybe an Opus script plus an autohotlkey script to send the [*] press would be more palatable...?
I spent over an hour this morning looking for AutoHotkey scripts earlier today, but I didn't find any that would activate the * key (other Windows keys, yes). With SetPoint, I click on the Libraries folder, then press a tiny button under my thumb to simulate the pressing of the * key, and this works well. I would like Directory Opus to save the expanded state natively, if ever possible, so I don't have to rely on 3rd party software. I'm going to start learning how to use the scripting feature. Once I get off Reddit. Sometime soon...
I really prefer having my Libraries folder at the top of the tree (Am I being picky? Maybe, but then again, Directory Opus is designed to be highly customized, right?). While putting the Libraries folder at the bottom of the Lister makes the direct sub-folders visible(\Google Drive and \Microsoft OneDrive, in my case), I am trying/wanting to make all sub-folders fully expanded and visible automatically when I launch a Lister. I've found a compromise that sort of does what I want - I assigned one of my mouse buttons to duplicate the pressing of the * key. However, I have to rely on SetPoint drivers to do this. I really don't like SetPoint, to be honest.