Can't Right click Merchants nor Give Items to NPC's

[Moonkey]

Got the Uncle (a fellow fan of EQ Classic) to start on the P99 Server. Everything seems to work fine but he's having a problem with Buying/Selling at Merchants and he also notes that he can't seem to give NPC's items to fulfill quests. He can Hail/talk to NPC's, he can target them, but, the much needed favorite past-time of right-clicking merchants and dropping items on NPC's to fulfill supply and demand (questing) seems to allude his experience.

He's playing windowed and 1st person, so i figure resolution settings and the annoying problem of clicking on your mysteriously "wide" self can be written off the list of potential causes.

I can't seem to find ANYTHING in all of my searches that really visits this specific problem. So I'm wondering if anyone has heard of this before? Something related that I'm missing? Anything really. If this is a first, I'll assume that it leans a bit more towards operator error, in that the 9 or so NPC's he tried right clicking were all non-merchants, but that wouldn't explain the lack of ability to give NPC's items. Only other thing I can think of is that these windows that pop up when vendoring or when "Giving" items to NPC's maybe they are hidden or off screen oddly enough.

I'm waiting for him to get home to try out some of these more self-fix things. Like seeing if the text comes up in chat when he right clicks a vendor and it says "hello such n such, you look like you could use a Fire Beetle Eye" or whatever they say. I figured I'd post just in case someone had heard of it a bit more on the Technical end of things. It's a slow process as he's not incredibly computer savvy and in another state. So, I'm hoping someone will have knowledge of this issue.

If you need computer specs, I'll have to get that information from him, but I would think it's semi irrelevant since the game appears to be working fine, minus these two fundamental In-Game functions.

Thanks in advance for any input. I apologize if this has been resolved or visited thoroughly before as again, I just could NOT find anything in all my searches.