I have just written about disabling password on login. Even when you do it, you are asked for password when coming back from idle. As if the system couldn’t figure out I do not want it there:
Luckily changing it is just few clicks away. It is not found under user settings but in screensaver settings. To get to it go to Menu-Preferences-Screensaver:
The option is right there. You have to uncheck the box: lock screen when screensaver is active.
You can also enable the password prompt window and change idle time to something more realistic than 5 minutes.