You can set up global function keys on the Hand-held GP so they can be used on all screens.
In this example, the [F1] key is set up as a global function key with a Window Display Switch operation.
You can set up the unit so that function key and touch panel operations work only when the Operation Switch (OP) is pressed.
5.4.3 System Settings [Display Unit] - [Operation] Settings Guide
One function key can be set up with both local and global function key operations.
41.3 Setting Up Function Keys on the Hand-held GP
41.4.1 Procedure - Setting Up Common Function Keys for All Hand-held GP Screens