Thank you for trying it! Those MDI titlebars/controls bother me too. I haven't decided what to do about it. Microsoft hasn't updated MDI functionality since Windows 7. These days, people simply don't use MDI at all.
Minimize is disabled because it's too buggy currently, but I plan to bring it back. In the old days it would minimize to an icon but these days it minimizes to a tiny sliver of a titlebar that's impossible to click on. For Program Manager, I implemented a manual workaround (literally, my own minimized icon bar), but I haven't implemented that in File Manager yet. Definitely something I have planned for the future.
Thanks for the tip about smooth scrolling. I have it disabled in Performance Options, so I never noticed.
MDI has never been updated for Windows 10 or newer. Which is a shame because even if it's not the modern way, older apps exist...
Delphi / C++Builder wrote a new implementation of MDI to keep older apps working, but looking modern. (It means MDI-architected apps can use, eg, tabs for windows too while keeping the old code the same.) https://blogs.embarcadero.com/3-x-12-vcl-enhancements-in-del...