New VST control does it work in the background?

Does anyone understand how “hover,” technology works? I’ve seen a recent slew of control surfaces that feature parameter control via mouse cursor hovering. Basically, take your mouse and hover it over a parameter, then twist the
knob on your control device and watch the VST parameter move. I recently purchased a Presonus Faderport 8 and it does this…I love it. However, it got me to thinking if there’s a way to extend that feature to other forms of custom designed controllers…but, first how the heck is that even being done? There’s no midi assignment that I’m aware of and while writing this, the forum showed me another thread about the Pass MouseEvent which kind of sounds like what I’m trying to do.

I want to do something similar with a hardware controller I’m building to control VSTs. My idea is to somehow( that’s the part I’m trying to figure out) control my larger VSTi plugins from a hardware controller without worrying about the limitations of MIDI. There are some behemoth VSTis out there with some 20K available parameters and while it sounds crazy to want to control all of them, it’s the sort of crazy project I’m interested in exploring. I know that MIDI can’t map to all those parameters and what it can map to is spread across 16 channels. I want to design something that communicates on 1 channel to whatever plugin is in focus. This “hover,” technology (sorry its the best description I have) sounds like the step in the right direction.

I hoping that understand how it works would give me some idea on how to use it in a different capacity or if something like that is even possible. Calling all smart people!!! Please share your thoughts!