Viewing call list during a call

Currently i'm using iphone4s with latest ios. It seems ios doesn't support viewing of the dial list during a call. More specifically, if you earlier dialed a number which is not saved in phone book, you can't see that number during next call. This seems bad. I had to tell the last dialed no to the person whom i was talking in the ne t call. I really had to disconnect, check/memorise the number and call again. I checked with latest windows, its missikg there as well. Any clue?