The interface in 'Desktop Behavior' -> 'Screen Locking' does not allow the user to set the screen to lock after more than 99 minutes. Please consider removing this limitation or at least making it larger. It's nice to be confident I can watch a long movie without having the screen lock on me before it's over. Reproducible: Always Steps to Reproduce: 1. Open System Settings 2. Navigate to 'Desktop Behavior' -> 'Screen Locking' 3. Try to set 'Lock screen after setting' to more than 99 minutes Actual Results: It is not possible to set the screen to lock after more than 99 minutes. Expected Results: It should be possible to set the screen to lock after at least a few hours.
*** This bug has been marked as a duplicate of bug 344967 ***
Also note that there is a public API an application can use to tell the system it doesn't want the screen to turn off automatically. There was a bug prior to Plasma 5.3 where this wouldn't work properly for 3rd party applications like VLC player. Please update your Plasma version.