Originally Posted by E-Phone
Setting the Left Side Convenience Key to Password Lock does actually work. Something should be wrong with your device. Another option is to use the Lock symbol that is available on one of the folders in your BB. Pressing "K" also works. All three options will password lock the device.
Well maybe for YOU but not for all of us...
Left side is indeed an option but I am using it for contacts which I use much more frequently than lock.
Using the Lock Icon of course works and this is what i use now to lock my BB.
Pressing K offers to assign a speed dial!
Of note the top button used to password lock the device when I was using OS 4.6.X.X