I would like to propose the following feature in Notepad++:
support backward and forward navigation inside a document, e.g. using the ALT+CURSOR LEFT/RIGHT keys. This feature is common in other editors, e.g. in MS Visual Studio. The editor remembers all previous cursor positions to allow backward navigation.
It could just perform history of line numbers where cursor was moved left or right, or where cursor was left for more than 2 seconds, or anything. Most word processors have back-forward history. Very important for navigation when studying code.
The Location Navigate plugin does that. It is available from the Plugins Manager inside Notepad++.