[#10] AreaComAdminWindow: Implement MVVM

Elwig/App.xaml.cs

@@ -272,7 +272,7 @@ namespace Elwig {
         }
 
         public static AreaComAdminWindow FocusMemberAreaComs(int mgnr) {
-            return FocusWindow<AreaComAdminWindow>(() => new(mgnr), w => w.MgNr == mgnr);
+            return FocusWindow<AreaComAdminWindow>(() => new(mgnr), w => w.ViewModel.Member.MgNr == mgnr);
         }
 
         public static BaseDataWindow FocusBaseData() {