Trap and release focus from elements
Use the buttons to trap or release the focus for the Callout.
You can then use the Tab key to focus the links in the Callout. If the focus is trapped, you shouldn't be able to focus any element outside of the Callout using Tab or Shift+Tab.
The following box binds to a regular keydown-event to check if the trapping and releasing does not interfere with other events.
Link 0 outside