Using the Media item lane in the MIDI editor in Automatic mode is such a breeze to work with. I use a lot of custom actions in the MIDI editor which require only the item I am editing to be selected in the arrange. (splitting, glue, take switching, etc...) So the automatic mode is the best option for me.
However, I would still prefer to see all the other item notes of the track I'm editing to be faintly drawn in the editor. - and to be able to click on them to switch the item and selection.
***edit**
uncheck "Media Item selection mirrors arrange view"
When you open all track MIDI, only one item is selected, and you can switch with a double click of a translucent event - however selection does not follow, like it did in 4.4. Also, if you then click on anything in the track list or media lanes, the drawn inactive notes disappear.
Basically, this is how it used to work.
There is no working method in this cycle to actually have it work like it did before regarding the edibility of the item, and item selection. (and still see all the notes in the track)
Backward compatibility should also pertain to methodology, no?