I tried to implement this code but the "chat" interaction button does not appear over the NPC's head. The only potential issue I noticed in your code is that there is a space between QuestGuy, and _Player. I think it should be:

KB:
IF
DialogStartRequested(CHARACTER_QuestGuy,_Player)
THEN
DialogStartTwoSpeakerDialog("QuestDialogue",CHARACTER_QuestGuy,_Player);

But when I tried that, it still didn't work. The code does build successfully so I'm not certain what's causing the issue.

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