Meadow and Grove biomes does not work in "Floating Islands" world type

I tried to make a grove biome with the floating islands preset, and all I got was endstone!
I tried it again with meadow biome, and same thing happened again!

 

*I'm pretty sure this happens with other mountain biomes as well, haven't checked it yet.

*Like "Floating islands" is related to endstone, probably "Caves" preset gives netherrack.