+ protected:
+ friend class ChangeSuspender;
+ static void suspend_change_signal ();
+ static void unsuspend_change_signal ();
+
+ public:
+ class ChangeSuspender {
+ public:
+ ChangeSuspender() {
+ PresentationInfo::suspend_change_signal ();
+ }
+ ~ChangeSuspender() {
+ PresentationInfo::unsuspend_change_signal ();
+ }
+ };
+