[MP4] Blue ground disappears after validating and saving a map

[SparklingW]

You can make blue ground disappear to set unbeatable author times using the setup I show in this image album:
I am not sure what exact block combination makes this happen, I assume it is the white roof above the quarter round white block (after further testing this setup is indeed what makes this happen, no other blocks necessary). This block normally makes the ground underneath blue, however after saving and exitting the map editor it seems to disappear.

This actually allows players to make unbeatable author time and possibly even unbeatable maps.