You can lock the items you dont want to sell. So you see only chunk on the sell list at th vendor.
Well, I would prefer, if I could sell all the junk at once. Not one by one.
I can already filter inventory to see only junk, so it is not problem. I don't see much advantage in locking items I don't want sell immediately.
Also a 'lock junk' option! I mark all my consumables and other stuff I use regularly as junk because don't want to see 50 items that I have in my inventory anyway when looking for that item which dropped.
If you're on pc the addon Dustman may be what you're wanting
Oh, thanks for pointing it. I was using it to mark and remember items as junk. But I had disabled option to "sell them automatically", so I needed hit button "sell all junk".
This solves it, at least for me, thank you.
Anyway, it is still option, which shoul be in the asistant's power.