I think this can be easily implemented. Current advanced targeting behavior when holding left mouse button to move, can cause to randomly open up a vendors interface when you hover near them (i know you can switch to old targeting behavior).
This is useful when targeting monsters, but it is a bit annoying against vendors/npc’s. Game has ideal behavior for this when you hover over chests for instance, you have to click again to that chest to open it (so holding doesn’t work). Why not apply this behavior to npc’s too? So if i want to talk to a vendor while holding left button, i have to release left button and click on that npc. I think this would be a nice small QoL change.