1) Check the time limit set on your device for locking the keyboard under Options>Password. Lets say you have it as 1 min.
2) Lock the keyboard using the'lock' button
3) Try to unlock after 1 min (or whatever time you have set under options>password)
4) It asks for the password
5) If the device is tried to unlock before the time set, it unlocks without asking for a password.
So, the password becomes functional ONLY at the timeout set by you.