Mouse targeting problem

[:1]Hi, so I have this problem where i move my mouse over a target lets say for instance an npc merchant. I move my mouse over to right click on them to vendor with them, but it doesnt target them.I ts simply like they are not there, and my mouse is in the middle of their body. But, how ever there is like 2 very small spots for each npc/real character that i can target and interact with. But it just gets on my nerves that i have to position it precisely. Is there anyway to fix this?