When I use Xcode 4.5.1 on my iMac it always starts downloading Mac OS 10.8 Core Library. If I use my MacBook Pro with same Xcode 4.5.1 it does not download anything.
Xcode in my iMac is updated several times during the last years but my MacBook Pro is new. And one more strange thing is when I updated my iMac´s Xcode from 4.5.0 to 4.5.1 it was like two sections, one which was as big as it said it would be and a second one much bigger (1.6 Gb) When updated my MacBook Pro it was just the first section and nothing more. It was a difference of time for updating from some minutes to an hour or so. Why? What is going on? What have I done or selected in the past to get this huge update and all this downloading?
I now know it is the documentation which is downloaded from http://developer.apple.com/rss/com.apple.adc.documentation.AppleOSX10_8.atom
It is found together with some other stuff under preferences, downloads.