The ability to resize the pane where search and favourites are shown
The size of the pane where the search appears and the favourites are shown are too wide. It would be great to be able to minimize it in order to have more space for the tools and chat people are working with .
The Expand button (arrows top right) are in a not intuitive place.
So this icon in the navigation pane...or...
copy the navigation functionality from OneNote Online: It has different options of hiding and showing. Briljant.