This is the FrKeys documentation.
When keyboard shortcuts are defined, an extra button appears in the FrKeys window:
This button allows you to turn the keyboard shortcuts on and off. When this button is pressed down, keyboard shortcuts are enabled, and pressing a key that is assigned to a character will type that character. When this button is unpressed (in the ‘up’ position), the key will have its normal effect.
This allows you to assign a character to a letter key (for example the ‘E’ key might type the Greek letter epsilon) or to a key that normally does something else (for example Ctrl+C which is normally ‘copy’ could be assigned to ‘ç’)—without losing the key’s original function. When you want to type the character, ensure that the keyboard shortcuts button is pressed. When you want to use the key’s normal behaviour, click on the keyboard shortcuts button again to unpresss it.