When you're using a lot of VST plugins, it can be tedious in software to keep looking up the routing. The only way to do it is on the General tab, you need to click on the Root VST plugin in the dropdown, then look at "output to" then use the dropdown again to navigate to the next plugin, look at "output to" and so on. Following the plugin up the chain 1 by 1.

It would be so much easier if I could see a visual of the plugin routing. I find myself having to create a diagram on a piece of paper to keep track of plugin routing, but if you re-route 1 VST, the diagram is useless.

I think there should be a 6th Tab with General, Patterns, Samples, Instruments Comments called "Plugins" that gives a dedicated page and shows a tree of how the plugins are routed. Instead of burying everything under 1 drop-down menu. Then you could just double-click on the instance to pull up the GUI. I used to use this Java software in school called BlueJ (see screenshot) and it would show class dependencies with arrows. I'd imagine this is how it could look in OpenMPT.