I have an HTC Droid Eris and was playing around and hit the home button when an option came up and asked me if I wanted to go to "Home" or "HTC Sense UI" and also gave me the option to use my selection as the default selection. I wasn't sure which one to pick, so I pressed "Home" and it took me to an entirely different home screen that looked sort of defaulted with just a few icons. All my icons were gone and the menu style was that of the Motorola Droid (with the pull up programs menu). It reminded me of switching operating systems on a computer. I found out I was able to hold down the home button and press on "HTC Sense UI" to return to my normal screens. My questions: what is this, how do I do it intentionally, and what is the purpose? I never knew this was an option and was actually quite worried when it happened until I found out I can switch back and forth.