when creating a partition and there's no available space or not enough available space (both situations), pop-up error dialog simply says: "Could not allocate requested partitions: Partitioning failed: Could not allocate partitions" a better error, specifically one that talks about the size being too big for the available space or "selected size not allocatable" or whatever would be much more helpful IMHO
Not sure what parted tells us but we can look into it.
Not going to do this at this point.