In some Xcode documentation, pageUp and pageDown (either via keyboard or mouse click in scroll bar) scrolls too far, by about the height of the header. OS X 10.9.1 13842. example: <REPLACE/WITH/$HOME>/Library/Developer/Shared/Documentation/DocSets/com.apple.adc.documentation.AppleOSX10.9.CoreReference.docset/Contents/Resources/Documents/documentation/Cocoa/Conceptual/EventOverview/EventHandlingBasics/EventHandlingBasics.html