Waiting for an email from a customer while eating your lunch and don't want your screen to go to sleep/lock. Want to stop your screen from locking while you wait for a program to install. Just leave this displayed as your main window and turn it on!
When the app is selected and the button is blue this will prevent your screen from locking on your system timeout. Just minimise the app, start using another app or set the button grey to allow your screen to lock as normal. You can resize this window as required.
Does not affect mouse or keyboard input like some other apps.