I think there was a post about omega somehow i could not find it ( is there any search function within this cfa 3? i am quite new to here sorry ;/ ) Could someone help why the delta of the bull spread is closed to 1? The answer is very unkind. 
probably meaning that bull spread delta could never be 1? it may approach 1, but never equal?
if constructed with long call w strike X1 and short call w strike X2, with X1
S< X1: combined delta will be somewhere in range 0…1, closer to 0, but positive (X2 option is deeper OTM)
X1>S>X2, X1 option delta is 1, X2 is ATM, thus combined also 0…1
S>X2: delta will be 0, since both long and short calls are in the money w deltas of 1
Hope i got it all right