There is a replacement for the current VerbCoin template that sounds a little like what you are asking for. I don't think many people have tried it, but you can download it from here if you want to give it a try. Maybe it will just be useful as an example of a context-sensitive GUI that pops-up, but the inventory system is pretty much the BASS one and I tried to keep it as simple as I could.
There also some basic instructions for it in the new manual:
https://adventuregamestudio.github.io/ags-manual/TemplateVerbcoin.html
Disclaimer: both of these items are effectively pre-release
There also some basic instructions for it in the new manual:
https://adventuregamestudio.github.io/ags-manual/TemplateVerbcoin.html
Disclaimer: both of these items are effectively pre-release