As you may recall, I implemented a basic OneNote-like Settings pane in .NETpad (UWP) where I can hide infrequently-accessed commands that the real Notepad places in menus (and sometimes in non-sensical places, in my opinion). This slide-in panel still needs some work---a shadow would be nice---but I think it looks great, and it feels like a native UWP-type interface.
As I noted last time, I struggled a bit with the underlying user settings that this Settings pane requires, but once that was out of the way, I moved on to some of the app’s other crucial functionality, like file save operations. But eventually I had to turn my attention to what I think of as Find/Replace, which is really a slew of related commands that includes, Find, Find Previous, Find Next, Replace, and Replace All. And implementing all that will require some new UI.