[BUG]Tiles Disappear, But Still Usable
http://screencast.com/t/VSQgfCHBP
This is a link to a video I made showcasing the effect.
To reproduce, all I've had to do is create a city and click around it until the tiles disappear. Tiles that cause this appear to be random (relative location does not affect it, nor does channeler location as I previously thought).
Hope that this helps.
PS: Jing is VERY useful. Thanks Frogboy for the great suggestion!