[Master] Unresponsive Quest Dialogue Buttons

Description: After turning in certain quests (I've encountered 3 in a row so far in the Blood Elf start zone) the quest box does not close after clicking [Complete Quest]. The reward populates the event box, and the reward subsequently appears in the inventory, but the dialogue box remains on screen until you manually close it. See photo:

http://i.imgur.com/MI1mZmZ.jpg

(I am aware of the fact that the currency test token issue was fixed in a commit and I will test this issue again after re-compiling.)

Current behaviour: See description.

Expected behaviour: On clicking "Complete Quest" the dialogue box should close sending you on your merry way. In this case it was quest "A Fistful of Slivers" # 8336.

Steps to reproduce the problem:

1. Roll a toon to the area and accept quest.
2. Acquire required materials for quest
3. Turn in and observe.

Branch(es): Master

TC rev. hash/commit: e0fb444

TDB version: 7.01

Operating system: Windows 10

Start by reproducing quest 8336, A Fistful of Slivers, on the Master branch using the listed steps and confirm whether the dialogue remains after completing the quest. Trace the quest-completion and dialogue handling involved; done means the dialogue closes after Complete Quest while the reward still appears in the event box and inventory.