I just noticed today that I can only see open seats in the class I am booked in (on Delta.com for Delta mainline flight).

If booked in economy, it used to be possible to see free seats in economy+ and first. In particular, for economy+ this was nice to check if it is worth it requesting an upgrade(and avoid getting "upgraded" from a nice exit seat to the last middle seat).

Is this a recent change? I don't remember seeing this last week. Or did I just catch delta.com on a bad day.