Recommended for iMac models released in late September 2013 (see “Apple Updates iMac with Faster CPUs and 802.11ac Wi-Fi,” 24 September 2013), Apple has issued iMac 10.8.5 Supplemental Update 1.0 for those models with an Nvidia GeForce GT 750M graphics processor running OS X 10.8.5 Mountain Lion. The update fixes two bugs: one that caused external drives to eject after the iMac goes to sleep and another that prevented certain USB Bluetooth adapters from working. (Free update, 17.1 MB)
Option-Click in Scroll Bars for Jump Scrolling
In Mac OS X in general, and thus in most native Mac OS X applications, hold down the Option key and click anywhere in a window's scroll bar to jump to that spot (rather than scrolling one screen). If you like this behavior, you can make it the default in the Appearance preference pane. For "Click in the scroll bar to:" select "Jump to here."