Originally Posted by Callistus
I simply don't understand. From your testimony, your OB is different. Mine has a setting (outside Wi-Fi settings - it's under Data settings) that selects when to use 3G when Wi-Fi is not available. Either we have completely different OBs or you are confused between two completely different menus.
I'm sorry that I can't help any further.
I followed your steps below and I have the same menus, so our OBs must be the same.
Press Menu button->Settings->Wireless & networks->Wi-Fi Settings->Menu button (again)->Advanced.
Under Wi-Fi sleep policy, choose the setting of your preference (I use "Never when plugged in". When not plugged, this setting turns off Wi-Fi when the screen is off.
Just that under the "Wi-Fi sleep policy", there is a line of small print (in cyan clolour) that reads "Specify when to switch from Wi-Fi to mobile data". Is yours the same? I am just confuse by this line of text. After clicking it, there are 3 options given - "When screen turns off", "Never when plugged in" and "Never". You never mentioned Data Settings in the above steps, only Wi-Fi Settings.