CotEditor
CotEditor copied to clipboard
Search in Outline Menu
In Xcode, when the Outline Menu is open you can type to filter the list and press enter to select an item.
There is also a keyboard shortcut to open the Outline Menu (Ctrl-6).
The search method should allow for abbreviated search. In my experience the best way to do this is to convert abc
to a regex pattern .*a.*b.*c.*
and then sort results by length - the shortest match is the most likely result.
I did not know this feature on Xcode. Looks interesting.
Because it seems they use not just simple AppKit components, it may take time to implement. But I'll dig it when I have time.
Apple provides sample code on how to implement this feature. See the accepted answer here:
https://stackoverflow.com/questions/31968959/intercepting-nsmenu-key-events
Sorry for taking the time. Finally, I added the outline filtering feature o the next CotEditor 4.1.0, but not in the outline menu in the navigation bar but in the outline pane in the side panel because of ease of implementation. Regarding the implementation of the navigation bar, it may take more, but I'll give it a try.

In addition, added the menu command to open the online menu to the Find menu so that users can add their favorite shortcut keys.
