AdministrationWindow: Fix default value handling

Elwig/Windows/AreaComAdminWindow.xaml.cs

@@ -58,6 +58,7 @@ namespace Elwig.Windows {
                 EditAreaCommitmentButton.IsEnabled = false;
                 DeleteAreaCommitmentButton.IsEnabled = false;
                 ClearOriginalValues();
+                ClearDefaultValues();
                 ClearInputs(validate);
                 ClearInputStates();
             }
@@ -66,6 +67,7 @@ namespace Elwig.Windows {
 
         private void FillInputs(AreaCom a) {
             ClearOriginalValues();
+            ClearDefaultValues();
 
             FbNrInput.Text = a.FbNr.ToString();
             MgNrInput.Text = a.MgNr.ToString();
@@ -84,9 +86,14 @@ namespace Elwig.Windows {
         }
 
         private async void InitInputs() {
+            ClearOriginalValues();
+            ClearDefaultValues();
+
             FbNrInput.Text = (await Context.NextFbNr()).ToString();
             MgNrInput.Text = Member.MgNr.ToString();
-            FinishInputFilling();
+
+            SetDefaultValue(FbNrInput);
+            ValidateRequiredInputs();
         }
 
         protected override async Task RenewContext() {