It's like I said. It's not possible. Will not work on MV. Because that also involves my core plugin you would need to change. I guess if another coder takes that, is better if he/she made his version. Unless it's comfortable to read my core plugin and message plugin understand how they work and create a version for MV.
There is this one for MV, but I never used it, don't know if it will work.
https://github.com/ossra/RPG-Maker-MV-Plugins/blob/master/Window/Ossra_Window-Sc...