fix event tabs not updating with group size changes

include/editor.h

@@ -208,7 +208,6 @@ private slots:
 
 signals:
     void objectsChanged();
-    void selectedObjectsChanged();
     void loadMapRequested(QString, QString);
     void wildMonDataChanged();
     void warpEventDoubleClicked(QString, int, Event::Group);

include/mainwindow.h

@@ -219,6 +219,7 @@ private slots:
     void on_toolButton_deleteObject_clicked();
 
     void addNewEvent(Event::Type type);
+    void displayEventTabs();
     void updateSelectedObjects();
     void updateObjects();