Can somebody help me please
 

I use GTKRaidiant 1.21 or summit
and i want to make water BUT when i do that and compile it a debug menu comes up saying "Entity 0, Brush 43: fog brush has mulitiple visible sides". it says that twice. And when i go to test the map the water comes up as black squares with white outlines

Is this normal for GTK??? or is there a problem

Please help:)