mono/monomac — pull request #81 by cwensley (2012-10-22 18:50:21+00:00)
Title: NSObject.PerformSelector should allow null for object

See docs: https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSObject_Class/Reference/Reference.html#//apple_ref/occ/instm/NSObject/performSelector:withObject:afterDelay: