diff --git a/Elwig/App.xaml.cs b/Elwig/App.xaml.cs
index 2ee7c6f..2644bce 100644
--- a/Elwig/App.xaml.cs
+++ b/Elwig/App.xaml.cs
@@ -46,7 +46,7 @@ namespace Elwig {
 
         protected void OnPrintingReadyChanged(EventArgs evt) {
             foreach (Window w in Windows) {
-                foreach (var b in Utils.FindVisualChilds<Button>(w).Where(b => "Print".Equals(b.Tag))) {
+                foreach (var b in Utils.FindAllChildren<Button>(w).Where(b => "Print".Equals(b.Tag))) {
                     b.IsEnabled = IsPrintingReady;
                 }
             }
diff --git a/Elwig/Helpers/Utils.cs b/Elwig/Helpers/Utils.cs
index f663ae9..5bece0c 100644
--- a/Elwig/Helpers/Utils.cs
+++ b/Elwig/Helpers/Utils.cs
@@ -7,7 +7,6 @@ using System.Windows;
 using System.Windows.Controls;
 using System.Diagnostics;
 using System.Windows.Controls.Primitives;
-using Microsoft.EntityFrameworkCore;
 
 namespace Elwig.Helpers {
     public static class Utils {
@@ -46,22 +45,36 @@ namespace Elwig.Helpers {
             return toggleButton?.Template.FindName("templateRoot", toggleButton) as Border;
         }
 
-        public static IEnumerable<T> FindVisualChilds<T>(DependencyObject depObj) where T : DependencyObject {
+        public static IEnumerable<T> FindAllChildren<T>(DependencyObject depObj) where T : DependencyObject {
             if (depObj == null)
                 yield return (T)Enumerable.Empty<T>();
-            for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++) {
-                DependencyObject ithChild = VisualTreeHelper.GetChild(depObj, i);
-                if (ithChild == null)
+            foreach (var child in LogicalTreeHelper.GetChildren(depObj)) {
+                if (child == null) {
                     continue;
-                if (ithChild is T t)
+                } else if (child is T t) {
                     yield return t;
-                foreach (T childOfChild in FindVisualChilds<T>(ithChild))
-                    yield return childOfChild;
+                } else if (child is DependencyObject childDepOpj) {
+                    foreach (T childOfChild in FindAllChildren<T>(childDepOpj)) {
+                        yield return childOfChild;
+                    }
+                }
             }
         }
 
-        public static IEnumerable<T> FindVisualChilds<T>(DependencyObject depObj, IEnumerable<DependencyObject> exempt) where T : DependencyObject {
-            return FindVisualChilds<T>(depObj).Where(c => !exempt.Contains(c));
+        public static IEnumerable<T> FindAllChildren<T>(DependencyObject depObj, IEnumerable<DependencyObject> exempt) where T : DependencyObject {
+            return FindAllChildren<T>(depObj).Where(c => !exempt.Contains(c));
+        }
+
+        public static T? FindNextSibling<T>(Control me) where T : DependencyObject {
+            var found = false;
+            foreach (var child in LogicalTreeHelper.GetChildren(me.Parent)) {
+                if (found && child is T c) {
+                    return c;
+                } else if (child == me) {
+                    found = true;
+                }
+            }
+            return null;
         }
 
         public static int Modulo(string a, int b) {
diff --git a/Elwig/Helpers/Validator.cs b/Elwig/Helpers/Validator.cs
index c1e95b5..1ea8042 100644
--- a/Elwig/Helpers/Validator.cs
+++ b/Elwig/Helpers/Validator.cs
@@ -30,7 +30,7 @@ namespace Elwig.Helpers {
             { "423", Array.Empty<string[]>() },
         };
 
-        public static ValidationResult CheckNumeric(TextBox input, bool required) {
+        public static ValidationResult CheckInteger(TextBox input, bool required) {
             return CheckNumeric(input, required, -1);
         }
 
@@ -257,7 +257,7 @@ namespace Elwig.Helpers {
         }
 
         public static ValidationResult CheckMgNr(TextBox input, bool required, AppDbContext ctx, Member? m) {
-            var res = CheckNumeric(input, required);
+            var res = CheckInteger(input, required);
             if (!res.IsValid) {
                 return res;
             } else if (!required && input.Text.Length == 0) {
@@ -273,7 +273,7 @@ namespace Elwig.Helpers {
         }
 
         public static ValidationResult CheckPredecessorMgNr(TextBox input, bool required, AppDbContext ctx) {
-            var res = CheckNumeric(input, required);
+            var res = CheckInteger(input, required);
             if (!res.IsValid) {
                 return res;
             } else if (!required && input.Text.Length == 0) {
@@ -296,7 +296,7 @@ namespace Elwig.Helpers {
         }
 
         public static ValidationResult CheckVNr(TextBox input, bool required, AppDbContext ctx, Contract? c) {
-            var res = CheckNumeric(input, required);
+            var res = CheckInteger(input, required);
             if (!res.IsValid) {
                 return res;
             } else if (!required && input.Text.Length == 0) {
diff --git a/Elwig/Windows/AdministrationWindow.cs b/Elwig/Windows/AdministrationWindow.cs
index f7c6f0b..45dd391 100644
--- a/Elwig/Windows/AdministrationWindow.cs
+++ b/Elwig/Windows/AdministrationWindow.cs
@@ -30,10 +30,10 @@ namespace Elwig.Windows {
         }
 
         private void OnLoaded(object sender, RoutedEventArgs evt) {
-            TextBoxInputs = Utils.FindVisualChilds<TextBox>(this, ExemptInputs).ToArray();
-            ComboBoxInputs = Utils.FindVisualChilds<ComboBox>(this, ExemptInputs).ToArray();
-            CheckBoxInputs = Utils.FindVisualChilds<CheckBox>(this, ExemptInputs).ToArray();
-            RadioButtonInputs = Utils.FindVisualChilds<RadioButton>(this, ExemptInputs).ToArray();
+            TextBoxInputs = Utils.FindAllChildren<TextBox>(this, ExemptInputs).ToArray();
+            ComboBoxInputs = Utils.FindAllChildren<ComboBox>(this, ExemptInputs).ToArray();
+            CheckBoxInputs = Utils.FindAllChildren<CheckBox>(this, ExemptInputs).ToArray();
+            RadioButtonInputs = Utils.FindAllChildren<RadioButton>(this, ExemptInputs).ToArray();
             foreach (var tb in TextBoxInputs)
                 Valid[tb] = true;
         }
@@ -250,5 +250,76 @@ namespace Elwig.Windows {
             UpdateButtons();
         }
 
+        protected void IntegerInput_TextChanged(object sender, RoutedEventArgs evt) {
+            InputTextChanged((TextBox)sender, Validator.CheckInteger);
+        }
+
+        protected void PartialDateInput_TextChanged(object sender, RoutedEventArgs evt) {
+            InputTextChanged((TextBox)sender, Validator.CheckPartialDate);
+        }
+
+        protected void DateInput_TextChanged(object sender, RoutedEventArgs evt) {
+            InputTextChanged((TextBox)sender, Validator.CheckDate);
+        }
+
+        protected void PlzInput_TextChanged(object sender, RoutedEventArgs evt) {
+            var plz = (TextBox)sender;
+            InputTextChanged(plz, Validator.CheckPlz);
+            UpdatePlz(plz, Utils.FindNextSibling<ComboBox>(plz));
+        }
+
+        protected void PlzInput_LostFocus(object sender, RoutedEventArgs evt) {
+            var plz = (TextBox)sender;
+            InputLostFocus(plz, Validator.CheckPlz);
+            UpdatePlz(plz, Utils.FindNextSibling<ComboBox>(plz));
+        }
+
+        protected void EmailInput_TextChanged(object sender, RoutedEventArgs evt) {
+            InputTextChanged((TextBox)sender, Validator.CheckEmailAddress);
+        }
+
+        protected void EmailInput_LostFocus(object sender, RoutedEventArgs evt) {
+            InputLostFocus((TextBox)sender, Validator.CheckEmailAddress);
+        }
+
+        protected void PhoneNrInput_TextChanged(object sender, RoutedEventArgs evt) {
+            InputTextChanged((TextBox)sender, Validator.CheckPhoneNumber);
+        }
+
+        protected void PhoneNrInput_LostFocus(object sender, RoutedEventArgs evt) {
+            InputLostFocus((TextBox)sender, Validator.CheckPhoneNumber);
+        }
+
+        protected void IbanInput_TextChanged(object sender, RoutedEventArgs evt) {
+            InputTextChanged((TextBox)sender, Validator.CheckIban);
+        }
+
+        protected void IbanInput_LostFocus(object sender, RoutedEventArgs evt) {
+            InputLostFocus((TextBox)sender, Validator.CheckIban);
+        }
+
+        protected void BicInput_TextChanged(object sender, RoutedEventArgs evt) {
+            InputTextChanged((TextBox)sender, Validator.CheckBic);
+        }
+
+        protected void BicInput_LostFocus(object sender, RoutedEventArgs evt) {
+            InputLostFocus((TextBox)sender, Validator.CheckBic);
+        }
+
+        protected void UstIdInput_TextChanged(object sender, RoutedEventArgs evt) {
+            InputTextChanged((TextBox)sender, Validator.CheckUstId);
+        }
+
+        protected void UstIdInput_LostFocus(object sender, RoutedEventArgs evt) {
+            InputLostFocus((TextBox)sender, Validator.CheckUstId);
+        }
+
+        protected void LfbisNrInput_TextChanged(object sender, RoutedEventArgs evt) {
+            InputTextChanged((TextBox)sender, Validator.CheckLfbisNr);
+        }
+
+        protected void LfbisNrInput_LostFocus(object sender, RoutedEventArgs evt) {
+            InputLostFocus((TextBox)sender, Validator.CheckLfbisNr);
+        }
     }
 }
diff --git a/Elwig/Windows/AreaComAdminWindow.xaml.cs b/Elwig/Windows/AreaComAdminWindow.xaml.cs
index 923cf7b..8c29221 100644
--- a/Elwig/Windows/AreaComAdminWindow.xaml.cs
+++ b/Elwig/Windows/AreaComAdminWindow.xaml.cs
@@ -448,7 +448,7 @@ namespace Elwig.Windows {
         }
 
         private void NumericInput_TextChanged(object sender, RoutedEventArgs evt) {
-            InputTextChanged((TextBox)sender, Validator.CheckNumeric);
+            InputTextChanged((TextBox)sender, Validator.CheckInteger);
         }
 
         private void VNrInput_TextChanged(object sender, RoutedEventArgs evt) {
@@ -460,11 +460,11 @@ namespace Elwig.Windows {
         }
 
         private void YearFromInput_TextChanged(object sender, RoutedEventArgs evt) {
-            InputTextChanged((TextBox)sender, Validator.CheckNumeric);
+            InputTextChanged((TextBox)sender, Validator.CheckInteger);
         }
 
         private void YearToInput_TextChanged(object sender, RoutedEventArgs evt) {
-            InputTextChanged((TextBox)sender, Validator.CheckNumeric);
+            InputTextChanged((TextBox)sender, Validator.CheckInteger);
         }
 
         private void GstNrInput_TextChanged(object sender, RoutedEventArgs evt) {
@@ -476,7 +476,7 @@ namespace Elwig.Windows {
         }
 
         private void AreaInput_TextChanged(object sender, RoutedEventArgs evt) {
-            InputTextChanged((TextBox)sender, Validator.CheckNumeric);
+            InputTextChanged((TextBox)sender, Validator.CheckInteger);
         }
     }
 }
diff --git a/Elwig/Windows/MemberAdminWindow.xaml b/Elwig/Windows/MemberAdminWindow.xaml
index 59f03d7..8b3bf08 100644
--- a/Elwig/Windows/MemberAdminWindow.xaml
+++ b/Elwig/Windows/MemberAdminWindow.xaml
@@ -140,7 +140,7 @@
 
                 <Label Content="Geburtstag:" Margin="10,100,0,0" Grid.Column="0"/>
                 <TextBox x:Name="BirthdayInput" Margin="0,100,0,0" Grid.Column="1" Width="78" TextAlignment="Right" HorizontalAlignment="Left"
-                         TextChanged="BirthdayInput_TextChanged"/>
+                         TextChanged="PartialDateInput_TextChanged"/>
 
                 <Label Content="Adresse:" Margin="10,130,0,0"/>
                 <TextBox x:Name="AddressInput" Margin="0,130,10,0" Grid.Column="1" Grid.ColumnSpan="3"
@@ -232,7 +232,7 @@
 
                 <Label Content="PLZ/Ort:" Margin="10,70,0,0" Grid.Column="0"/>
                 <TextBox x:Name="BillingPlzInput" Margin="0,70,0,0" Width="42" Grid.Column="1" HorizontalAlignment="Left"
-                         TextChanged="BillingPlzInput_TextChanged" LostFocus="BillingPlzInput_LostFocus"/>
+                         TextChanged="PlzInput_TextChanged" LostFocus="PlzInput_LostFocus"/>
                 <ComboBox x:Name="BillingOrtInput" ItemTemplate="{StaticResource PostalDestComboBoxTemplate}" TextSearch.TextPath="Ort.Name"
                           SelectionChanged="ComboBox_SelectionChanged"
                           Margin="47,70,10,0" Grid.Column="1"/>
@@ -247,16 +247,16 @@
                 </Grid.ColumnDefinitions>
 
                 <Label Content="Eintritt:" Margin="10,10,0,0" Grid.Column="0"/>
-                <TextBox x:Name="EntryDateInput" Margin="0,10,10,0" Width="78" Grid.Column="1" HorizontalAlignment="Left"  TextAlignment="Right"
+                <TextBox x:Name="EntryDateInput" Margin="0,10,10,0" Width="78" Grid.Column="1" HorizontalAlignment="Left" TextAlignment="Right"
                          TextChanged="DateInput_TextChanged"/>
 
                 <Label Content="Austritt:" Margin="10,40,0,0" Grid.Column="0"/>
-                <TextBox x:Name="ExitDateInput"  Margin="0,40,10,0" Width="78" Grid.Column="1" HorizontalAlignment="Left" TextAlignment="Right"
+                <TextBox x:Name="ExitDateInput" Margin="0,40,10,0" Width="78" Grid.Column="1" HorizontalAlignment="Left" TextAlignment="Right"
                          TextChanged="DateInput_TextChanged"/>
 
                 <Label Content="Geschäftsanteile:" Margin="10,70,0,0" Grid.Column="0"/>
-                <TextBox x:Name="BusinessSharesInput" Margin="0,70,10,0" Width="48" Grid.Column="1" HorizontalAlignment="Left"  TextAlignment="Right"
-                         TextChanged="NumericInput_TextChanged"/>
+                <TextBox x:Name="BusinessSharesInput" Margin="0,70,10,0" Width="48" Grid.Column="1" HorizontalAlignment="Left" TextAlignment="Right"
+                         TextChanged="IntegerInput_TextChanged"/>
 
                 <Label Content="BH-Konto:" Margin="10,100,0,0" Grid.Column="0"/>
                 <TextBox x:Name="AccountingNrInput" Margin="0,100,10,0" Grid.Column="1"
diff --git a/Elwig/Windows/MemberAdminWindow.xaml.cs b/Elwig/Windows/MemberAdminWindow.xaml.cs
index 1706242..98543ba 100644
--- a/Elwig/Windows/MemberAdminWindow.xaml.cs
+++ b/Elwig/Windows/MemberAdminWindow.xaml.cs
@@ -86,6 +86,7 @@ namespace Elwig.Windows {
                 EditMemberButton.IsEnabled = false;
                 DeleteMemberButton.IsEnabled = false;
                 AreaCommitmentButton.IsEnabled = false;
+                ClearOriginalValues();
                 ClearInputs();
             }
             if (!validate) ClearInputStates();
@@ -393,10 +394,9 @@ namespace Elwig.Windows {
             FillOriginalValues();
         }
 
-        protected void ClearInputs() {
+        new protected void ClearInputs() {
             Menu_Member_SendEmail.IsEnabled = false;
             AreaCommitment.Text = "- m²";
-            ClearOriginalValues();
             base.ClearInputs();
         }
 
@@ -415,10 +415,6 @@ namespace Elwig.Windows {
             InputLostFocus(input, checker(input, SenderIsRequired(input), Context, (Member)MemberList.SelectedItem), msg);
         }
 
-        private void NumericInput_TextChanged(object sender, RoutedEventArgs evt) {
-            InputTextChanged((TextBox)sender, Validator.CheckNumeric);
-        }
-
         private void MgNrInput_TextChanged(object sender, RoutedEventArgs evt) {
             InputTextChanged((TextBox)sender, Validator.CheckMgNr);
         }
@@ -434,81 +430,5 @@ namespace Elwig.Windows {
         private void PredecessorMgNrInput_LostFocus(object sender, RoutedEventArgs evt) {
             InputLostFocus((TextBox)sender, Validator.CheckPredecessorMgNr);
         }
-
-        private void BirthdayInput_TextChanged(object sender, RoutedEventArgs evt) {
-            InputTextChanged((TextBox)sender, Validator.CheckPartialDate);
-        }
-
-        private void PlzInput_TextChanged(object sender, RoutedEventArgs evt) {
-            InputTextChanged((TextBox)sender, Validator.CheckPlz);
-            UpdatePlz((TextBox)sender, OrtInput);
-        }
-
-        private void PlzInput_LostFocus(object sender, RoutedEventArgs evt) {
-            InputLostFocus((TextBox)sender, Validator.CheckPlz);
-            UpdatePlz((TextBox)sender, OrtInput);
-        }
-
-        private void PhoneNrInput_TextChanged(object sender, RoutedEventArgs evt) {
-            InputTextChanged((TextBox)sender, Validator.CheckPhoneNumber);
-        }
-
-        private void PhoneNrInput_LostFocus(object sender, RoutedEventArgs evt) {
-            InputLostFocus((TextBox)sender, Validator.CheckPhoneNumber);
-        }
-
-        private void EmailInput_TextChanged(object sender, RoutedEventArgs evt) {
-            InputTextChanged((TextBox)sender, Validator.CheckEmailAddress);
-        }
-
-        private void EmailInput_LostFocus(object sender, RoutedEventArgs evt) {
-            InputLostFocus((TextBox)sender, Validator.CheckEmailAddress);
-        }
-
-        private void IbanInput_TextChanged(object sender, RoutedEventArgs evt) {
-            InputTextChanged((TextBox)sender, Validator.CheckIban);
-        }
-
-        private void IbanInput_LostFocus(object sender, RoutedEventArgs evt) {
-            InputLostFocus((TextBox)sender, Validator.CheckIban);
-        }
-
-        private void BicInput_TextChanged(object sender, RoutedEventArgs evt) {
-            InputTextChanged((TextBox)sender, Validator.CheckBic);
-        }
-
-        private void BicInput_LostFocus(object sender, RoutedEventArgs evt) {
-            InputLostFocus((TextBox)sender, Validator.CheckBic);
-        }
-
-        private void UstIdInput_TextChanged(object sender, RoutedEventArgs evt) {
-            InputTextChanged((TextBox)sender, Validator.CheckUstId);
-        }
-
-        private void UstIdInput_LostFocus(object sender, RoutedEventArgs evt) {
-            InputLostFocus((TextBox)sender, Validator.CheckUstId);
-        }
-
-        private void LfbisNrInput_TextChanged(object sender, RoutedEventArgs evt) {
-            InputTextChanged((TextBox)sender, Validator.CheckLfbisNr);
-        }
-
-        private void LfbisNrInput_LostFocus(object sender, RoutedEventArgs evt) {
-            InputLostFocus((TextBox)sender, Validator.CheckLfbisNr);
-        }
-
-        private void BillingPlzInput_TextChanged(object sender, RoutedEventArgs evt) {
-            InputTextChanged((TextBox)sender, Validator.CheckPlz);
-            UpdatePlz((TextBox)sender, BillingOrtInput);
-        }
-
-        private void BillingPlzInput_LostFocus(object sender, RoutedEventArgs evt) {
-            InputLostFocus((TextBox)sender, Validator.CheckPlz);
-            UpdatePlz((TextBox)sender, BillingOrtInput);
-        }
-
-        private void DateInput_TextChanged(object sender, RoutedEventArgs evt) {
-            InputTextChanged((TextBox)sender, Validator.CheckDate);
-        }
     }
 }