What are those modifier keys?
As you know, there are 4 modifier keys for Mac, i.e. caps, 
Is it useful?
You can use modifier key to combine with other key. As we know that, caps is rarely used. Therefore, if you want to disable this key, you may follow this article.
Disable or change modifier key
- Move forward to Keyboard & Mouse Pane, QuickSilver way is keypref
- Seek through Keyboard tab and obviously there will be button so called 'Modifier Keys...'
- Click and those 4 modifiers action will be displayed
- They can be disabled or can be assign different action, e.g.
capsset to
