Glock Heinie sight - technical

[YVK]

Gents, I found that a Heinie sight on my Glock 19 started to move freely side to side. After I re-zero it, what do I need to do to prevent this from happening again? Loctite on the set screw? Loctite inside the sight cut? Blue? Red? Anything else?

Thank you.

[mvician]

If it was mine, yes, loctite, red.
Tighten the set screw, and then apply loctite around the base of the sight like they do with XS sights.

http://www.youtube.com/watch?v=ISUMmXiZMGw&feature=related