The lock screen isn't displayed immediately after resuming from sleep. Instead, the original contents of the screen are shown for a couple of seconds.

Version:
gdm-3.16.1.1-1.fc22.x86_64

Steps to reproduce:
1. Close laptop lid and wait for it to go to sleep
2. Open laptop lid

Actual result:
For a few seconds, the screen remains as it was before you put the machine to sleep. Then the lock screen appears.

Expected result:
Lock screen should appear immediately without delay and the contents of the screen (as it was before putting the machine to sleep) should not be shown until the user unlocks it.