It use to be that way, but was considered a cheat. If someone goes through all the trouble of positioning himself to attack out of the sun you shouldn't be able to defeat the tactic by keeping the notepad over it.
Learn to move your head around in the cockpit to block to sun, just don't save the position.
You mean your head position can move?
Seriously, it is a convenience feature, that's all. Yes you can hide your face behind a frame on a long bomber mission, true enough. Sometime when a CV is headed directly into a low sun you have to look sideways to see the clipboard. Anyway, just a convenience, but I think a nice one.