updates the enabled state for each navigation button . concode_field_sep Action backAction concode_elem_sep Action forwardAction concode_elem_sep DrillStack fDrillStack concode_elem_sep TreeViewer fChildTree concode_elem_sep Action homeAction concode_field_sep void addNavigationActions concode_elem_sep void addNavigationActions concode_elem_sep boolean canGoBack concode_elem_sep boolean canGoInto concode_elem_sep void createActions concode_elem_sep void goHome concode_elem_sep boolean canGoHome concode_elem_sep List getExpanded concode_elem_sep void goInto concode_elem_sep void goInto concode_elem_sep boolean canExpand concode_elem_sep void goBack concode_elem_sep void expand concode_elem_sep void selectionChanged concode_elem_sep void reset
void function ( ) { if ( homeAction != null ) { homeAction . setEnabled ( canGoHome ( ) ) ; backAction . setEnabled ( canGoBack ( ) ) ; forwardAction . setEnabled ( canGoInto ( ) ) ; } }