Activate 2 up display on edge selection

This is another basic editing feature that Apple is not giving us even though it has been requested several times by different people:

When you want to trim a clip the only way to get the 2 up display for feedback is to click and drag an edge of a clip. That’s the only way to see the outgoing and the incoming frames next to each other. If you use the keyboard for trimming that 2 up display doesn’t show up at all.

I would like to be able to bring it up automatically when an edge of a clip is selected for trimming as a preference so it can be on or off (and maybe also under command too).