it is showing requisites for the active character which is not the same a the one of the inventory. You also need to have your character active to put something on his quickbar.
I gotta do all that? That's ridiculous and counterintuitive. This is probably a bug or an oversight. I don't remember this happening in previous version. I recall saying a few times and seeing other people do so as well that switching to other character's inventory should automatically make that character the active one\selected. Making that heppen would resolve these kinds of counterintuitive UI bugs\features.
