XmGetFocusWidget — Returns the ID of the widget that has keyboard focus "XmGetFocusWidget" "traversal

XmGetFocusWidget examines the hierarchy that contains the specified widget and  returns  the  ID  of  the
       widget  that  has  keyboard  focus. The function extracts the widget ID from the associated Shell widget;
       therefore, the specified widget can be located anywhere in the hierarchy.

       widget    Specifies a widget ID within a given hierarchy

XmGetFocusWidget  —  Returns  the  ID of the widget that has keyboard focus "XmGetFocusWidget" "traversal
       functions" "XmGetFocusWidget"

XmProcessTraversal(3).

                                                                                             XmGetFocusWidget(3)

       Returns the ID of the widget with keyboard focus. If no child  of  the  Shell  has  focus,  the  function
       returns NULL.

       #include <Xm/Xm.h>
       WidgetXmGetFocusWidget(
       Widgetwidget);