As title says, please let us lock companion gear.
While questing and exploring, I like to have my companion in armor/weapons that she hasn't fully leveled yet, so she can level those skill lines. HOWEVER, when I come across a hard world boss/harrowstorm etc., I want to equip her with her BEST weapon, armor and skills. This means that I carry around 2 sets of gear for her.
Currently, companion gear cannot be locked (neither can it be marked as junk), so it is VERY easy to accidentally sell. Selling super expensive pieces of companion gear is mortifying. PLEASE PLEASE PLEASE let us lock it!
I see there have been a bunch of threads about this in the past. I'm amazed this hasn't been implemented yet, as it seems like such an obvious and straightforward change to make.