Specifies whether the input focus can enter the widget or any of its children.
Applications should set
can_focus to false to mark a widget as for pointer/touch use only.
Note that having
can_focus be true is only one of the necessary conditions for being focusable.
A widget must also be sensitive and focusable and not have an ancestor that is marked as not can-focus in order to receive input focus.
See grab_focus for actually setting the input focus on a widget.
whether or not the input focus can enter the widget or any of its children