In the old OneBag items you moved to mailbox attachment or tradewindow didn't get greyed out correctly. They eventually did but it took too long time. I think I reported it in the old topic but it was never fixed.
Continuing on grey stuff, I think it would be nice with a heavy marker on vendor items (grey) so you can easily sell them to the vendor. Don't know what is easy, but maybe a grey X over the icon or something to mark it as grey. A border like how rare/epic etc items are marked is not good, it should be a different and clearly visible marker.