It's similar to the following topic:

https://tweaker.userecho.com/topics/285-center-taskbar-icons

It's not possible at this time.

Great. Regarding the unlimited width, I'm not familiar of such a configuration, and the tweaker has no relevant option for that.

Try setting the always_show_tooltip advanced option to 2. Refer to the help file for more details.

By the way, setting the Hovering -> List option in the tweaker has the same effect as setting NumThumnails.

It can be configured with the advanced options. Right click on the tweaker's tray icon, choose "Advanced options", and go to the "Mouse Button Control" tab. Refer to the help file (the Help button) for information.

Yeah, it can be confusing with this setup. It's clearer if thumbnails or a list (and not only a tooltip) is shown on hover. It would also be clearer if the icons would be different. A potential enhancement can involve adding some kind of a visual indicator or animation to make it clearer that the re-ordering takes place. Maybe one day...

I assume you're talking about the "Drag within/between groups using right mouse button" option? Did I get it right that all other options work, but this option has no effect? As in, you hold your right mouse button, move it within a group, and nothing happens? Did the option work before?

Just to avoid confusion, please see the short video here and make sure that you're trying to use the option correctly.

This leaves me with right clicking and selecting 'close' as the fastest option to close a window.

You can also configure the middle click, or any other combination (such as Ctrl+click), to close a window.

It's not related to the options, the error happens before the options take place. I also can't think why Discord would be relevant, but you can test it by exiting it and checking whether the error persists.

Did you enable the virtual_desktop_order_fix advanced option?

I'm not sure what else I can put in a debug version. I already know that the CreateWindow function fails, which is rather strange since the call is quite simple and the function is very common. I wanted to reproduce it to be able to debug the process, as well as look at the environment at the moment of the error, such as what windows are open.

Perhaps you can take a clean system or virtual machine, and try installing the programs you have on your system until you're able to reproduce the problem. Then I'll be able to follow these steps by installing these programs, and to debug it locally.