Make setSensitive() and isSensitive() virtual.

Also, ass some assertions.

cmd/xfe/src/Component.cpp

@@ -122,13 +122,13 @@ XFE_Component::setBaseWidget(Widget w)
   m_widget = w;
 }
 //////////////////////////////////////////////////////////////////////////
-void
+/* virtual */ void
 XFE_Component::setSensitive(Boolean sensitive)
 {
   XtSetSensitive(m_widget, sensitive);
 }
 //////////////////////////////////////////////////////////////////////////
-Boolean
+/* virtual */ Boolean
 XFE_Component::isSensitive()
 {
   return XtIsSensitive(m_widget);
@@ -320,7 +320,9 @@ XFE_Component::getShowHideLabelString(char* cmd, Boolean show, Widget widget)
 void
 XFE_Component::installDestroyHandler()
 {
-  XtAddCallback(m_widget, XmNdestroyCallback, destroy_cb, this);
+	XP_ASSERT( isAlive() );
+
+	XtAddCallback(m_widget, XmNdestroyCallback, destroy_cb, this);
 }
 //////////////////////////////////////////////////////////////////////////
 void

cmd/xfe/src/Component.h

@@ -45,8 +45,8 @@ public:
     
   XFE_Component *getToplevel();
 
-  void setSensitive(Boolean sensitive);
-  Boolean isSensitive();
+  virtual void setSensitive(Boolean sensitive);
+  virtual Boolean isSensitive();
 
   virtual void show();
   virtual void hide();