The key to help remember this one, is to think of the CTRL+END as tieing the viewport to the end. As soon you "mouse around" or navigate using keystrokes, you're now specifying where you want the view port to focus on. Next, you need to CTRL+END to lock it at the end again. Yup, very useful feature. Some other programs have this implemented as well. Very cool IMHO!

Glad I found this page, just another one of those quirky bits of info that are sooo valuable. Thanks :)

Me and my restored sanity thank you!