Well, that's not exactly what i wanted. I made a Shrublands Biome and wanted to use it as a border for a desert, so a desert doesn't instantly is next to perfectly green grass or something, but i also have some "fade" biomes, so the sand fades into grass, thats the border biome i first use. I then would have to define the Shrublands as border biome of the Sand fade biome, but it's not working at all. Sometimes it gets randomly generated correct, like in this screen:
But then sometimes it doesn't.
EDIT: Oh, so you mean when i assign both biomes to desert and give the sand fade biome a smaller size?