I've been using Notebook for about a year, syncing notes between an iPhone and two Macs.  I prefer in Preferences, to set my "Sort by" to "Custom (Drag & Drop based on your requirements)".

Very frequently when I restart Notebook, or even just wake up the Mac to start a new work session, I notice the ordering of all of my notes has changed, go back to Preferences / Sort by, and find it has reverted to sorting them by "Updated date (Newest first)".  So I change it back to "Custom (Drag & Drop based on your requirements)".  I do this over and over and over.  Between the three devices, I'm probably having to change the sort order back to my preference about a dozen times a week.  This is very annoying; please fix!