I take it there's no demo version of these libraries available?

Virharmonic has a free library at https://www.virharmonic.com/violin_freebie
I haven't tested if that includes a GUI within it with buttons to click, etc.

Note that the free iLok software is required to run UVI Workstation.

I will also try to reproduce this on the weekend using any free libraries I can find, but 99% of UVI Workstation libraries are commercial.

Thanks!

Sorry, I had to cancel the installation of UVI Workstation as soon as it wanted to install PACE drivers on my system. I will not install anything like this crippleware. But I got in touch with the UVI developers to see if they can help resolving the issue.

Thank you for looking into it.

Today, I tested it with the free cowbells at http://www.vilabsaudio.com/truecowbells . I understand your hesitance about crippleware. I only started buying these libraries once the companies removed the usb-dongle requirement. (But to warn again, the web-shop above for the free cowbells library only worked for me in internet explorer (what decade is this?)).

It's the same issue, so it isn't just the virharmonic libraries for UVI Workstation but rather all of them that have a clickable GUI that are incompatible with OpenMPT. The cowbells library only has one clickable button, settings, to bring up an entirely different window, but the window never appears.

Well, hopefully they will respond to my mail, as I don't see how this could be OpenMPT's fault. OpenMPT does not manage additional windows opened by plugins, and there are plenty of plugins which open additional windows. Of course you can try mailing the UVI staff as well, but I can already see how they will go all "you are using a host we don't support, we are not going to help you".

I mailed UVI, choosing "Other" for host. We'll see.

The UVI plugin libraries don't open other windows so much as put their GUI into the space in the UVI window allotted to them.

http://i.imgur.com/SAUAELZ.jpg

Everything in the red rectangle I drew is unresponsive. Everything outside it works fine.

I can't imagine what the issue is, but OpenMPT is my favorite music software and the Virharmonic libraries in UVI Workstation make up about 40 minutes of the next two hours of music I'm making ;)

I received a response from one company as follows:

"If the GUI is unresponsive, no audio is linked. In other words there is no audio card/asio driver active/Audio unit linked in the instance of the UVI. This can happen if [the plugin/library/soundbank] isn't linked to a server instance or if they work in their daw in off line mode."

So does this mean that it doesn't work while OpenMPT isn't outputting any sound, but it works when it does? Or does it still not work at all?

If I hit play for the song or pattern, as long as it is playing, I can use the GUI!

Ok, so there's nothing really we can do, at least not as long as OpenMPT stops sound output when stopping playback. Maybe they will fix their plugin so that its GUI still works when there are no process calls...

I am now in direct contact with the actual UVI developer. For clarity, he'd like to know what exactly in the UI for you.

http://i.imgur.com/SAUAELZ.jpg

Everything in the red rectangle I drew is unresponsive. Everything outside it works fine. I'm guessing that's what you meant?

The person from the third-party company who wrote me about how libraries are only responsive if there is an "audio card/asio driver active/Audio unit linked in the instance of the UVI" also said "This is generic for all UVI instruments to my knowledge."

Yeah, apparently it basically boils down that for increased simplicity for library authors, they do library UI processing in the audio thread, which is dangerous bad practice but it cannot be changed for now. So if you need to access the UI of this plugin, always keep OpenMPT's audio output running.