diff --git a/Elwig/Windows/AdministrationWindow.cs b/Elwig/Windows/AdministrationWindow.cs
index 15be937..80bed34 100644
--- a/Elwig/Windows/AdministrationWindow.cs
+++ b/Elwig/Windows/AdministrationWindow.cs
@@ -201,6 +201,7 @@ namespace Elwig.Windows {
             Utils.RenewItemsSource(ortInput, list, i => (i as AT_PlzDest)?.Id);
             if (list != null && ortInput.SelectedItem == null && list.Count == 1)
                 ortInput.SelectedItem = list[0];
+            UpdateComboBox(ortInput);
         }
 
         protected bool InputTextChanged(TextBox input, Func<TextBox, bool, ValidationResult> checker) {
@@ -280,22 +281,31 @@ namespace Elwig.Windows {
             UpdateButtons();
         }
 
-        protected void ComboBox_SelectionChanged(object sender, RoutedEventArgs evt) {
-            var input = (ComboBox)sender;
-            if (input.ItemsSource != null && input.SelectedItem == null && RequiredInputs.Contains(input)) {
-                ValidateInput(input, false);
-                Utils.SetInputInvalid(input);
-            } else {
+        private void UpdateComboBox(Control input) {
+            bool valid = false;
+            if (input is ComboBox cb) {
+                valid = cb.ItemsSource == null || cb.SelectedItem != null || !RequiredInputs.Contains(input);
+            } else if (input is CheckComboBox ccb) {
+                valid = ccb.ItemsSource == null || ccb.SelectedItem != null || !RequiredInputs.Contains(input);
+            }
+            if (valid) {
                 ValidateInput(input, true);
                 if (InputHasChanged(input)) {
                     Utils.SetInputChanged(input);
                 } else {
                     Utils.ClearInputState(input);
                 }
+            } else {
+                ValidateInput(input, false);
+                Utils.SetInputInvalid(input);
             }
             UpdateButtons();
         }
 
+        protected void ComboBox_SelectionChanged(object sender, RoutedEventArgs evt) {
+            UpdateComboBox((Control)sender);
+        }
+
         protected void IntegerInput_TextChanged(object sender, RoutedEventArgs evt) {
             InputTextChanged((TextBox)sender, Validator.CheckInteger);
         }