Not to contradict my betters
nor to contradict the developers
but...
even though clicking on the lips is the "right way" to answer quest questions, I have found that it is still possible to answer the questions by typing in responses...
so even when a certain quest dialogue is buggy, you can still move ahead in the quest sometimes by typing the answer in that the npc won't accept from the buggy text box
AND
for general knowledge questions like
/about windowless tower
/about Talad
/about diamond
you can still type in the {slash} /about something and get useful knowledge from many npcs...
Roled Rolak
old school guy getting around some of the glitches...