Allow the control to

1. receives focus using the Tab key
2. display an indicator/border when a toolbar item receives focus
3. have a tab stop for any of its buttons

Allow the user to:

1.  tab into the control
2.  tab out of the control without being trapped
3. Shift + Tab navigate in reverse order correctly

The scenario should be implemented in the toolbar and inherited from the controls that use toolbar, like PDFToolbar