Draw distance calculation bug?

[moon]

Greetings,

Following problem appears here:
I made a quick custom level with own 3d objects and textures, a foggy level. When i came to the windows, wich have a translucent texture with refactions it where no problem so far, until i expanded the level and something got messed up when i multi selected a whole floor wall set inclusive windows, duplicated them and dragged them on another side of the level. Now the windows are drawn in wrong order and dissapear in the near and appear in the far, they are fading away and coming back again like the engine wouldn't know where the player is and where the windows are. A new placing of them didn't solved the problem.
Here is a Video of it:
http://rapidshare.com/files/424794536/2010-10-13.AVI

and here is the buggy map prepared as custom story:
http://rapidshare.com/files/424792075/soms.rar