In the threepages example the Android back button closes the app when you open mainpage than page 2 .
Should it not open the mainpage ? The people are used to go back via back button.
There is a Big Bug: to go back to the Main page, you have to tap con the "right oriented" arrow on bottom of screen (exit from current "activity"), but to exit from the "Draw Something" page to return to Page 2 the arrow (on top-left) is "left oriented".
This was done intentionally of course to show the different behavior. The idea is that we don't want the user to mistakenly log out by clicking on the back key.