Setup plays into creating 5th primary partition

Tested 0.4.2, R73093 using VirtualBox:
In the partition creation menu, Setup allows one to create 4 primary partitions, and then, if there are free space left, it allows one to go for creating the 5th primary partition (which, AFAIK is not possible) – opens the dialog to choose the partition size, and if ENTER is pressed – hangs.