Focus events
OnUp
The user press the change focus to previous control.
OnDown
The user press the change focus to next focus control.
OnLeft
The user wants to decrease the value shown to the control to be decreased.
OnRight
The user wants to decrease the value shown to the control to be increased.
OnEnter
The user wants to apply all settings from current screen and if are more screens, to go to following screen. Ussually on OnEnter command the $next command will follow.
OnCancel
The user wants to cancel all settings from current screen and if are more screens, to go to previous screen. Usually on OnCancel command the $previous command will follow.
OnFocus
If special code should run when a button is enable, you may override that event (for instance to play a small sound here)
OnLostFocus
If special code should run when a button becomes disable, you may override that event (for instance to play a small sound here)