diff --git a/FasdDesktopUi/Basics/UserControls/Ticket/CloseCaseDialogWithTicket.xaml b/FasdDesktopUi/Basics/UserControls/Ticket/CloseCaseDialogWithTicket.xaml
index 5c0adf5..f72394f 100644
--- a/FasdDesktopUi/Basics/UserControls/Ticket/CloseCaseDialogWithTicket.xaml
+++ b/FasdDesktopUi/Basics/UserControls/Ticket/CloseCaseDialogWithTicket.xaml
@@ -175,15 +175,16 @@
                                   Margin="0 10 0 0"
                                   Foreground="{DynamicResource FontColor.Menu.Categories}" />
 
-                            <ComboBox x:Name="QuickTicketSelection"
-                                 Margin="0 5 0 0"
-                                 Background="{DynamicResource BackgroundColor.DetailsPage.DataHistory.ValueColumn}"
-                                 BorderBrush="{DynamicResource BackgroundColor.Menu.SubCategory.Hover}"
-                                 SelectedIndex="0"
-                                 PreviewKeyDown="Combobox_PreviewKeyDown"
-                                 DropDownOpened="DropDownOpened"
-                                 DropDownClosed="DropDownClosed">
-                            </ComboBox>
+                            <ComboBox x:Name="QuickTicketSelection"
+                                 Margin="0 5 0 0"
+                                 Background="{DynamicResource BackgroundColor.DetailsPage.DataHistory.ValueColumn}"
+                                 BorderBrush="{DynamicResource BackgroundColor.Menu.SubCategory.Hover}"
+                                 SelectedIndex="0"
+                                 SelectionChanged="QuickTicketSelection_SelectionChanged"
+                                 PreviewKeyDown="Combobox_PreviewKeyDown"
+                                 DropDownOpened="DropDownOpened"
+                                 DropDownClosed="DropDownClosed">
+                            </ComboBox>
                         </StackPanel>
                         <StackPanel Orientation="Horizontal">
                             <TextBlock x:Name="SetOrUpdateComputerInTicketLabel"
diff --git a/FasdDesktopUi/Basics/UserControls/Ticket/CloseCaseDialogWithTicket.xaml.cs b/FasdDesktopUi/Basics/UserControls/Ticket/CloseCaseDialogWithTicket.xaml.cs
index 68bd5ec..2189121 100644
--- a/FasdDesktopUi/Basics/UserControls/Ticket/CloseCaseDialogWithTicket.xaml.cs
+++ b/FasdDesktopUi/Basics/UserControls/Ticket/CloseCaseDialogWithTicket.xaml.cs
@@ -74,6 +74,9 @@ namespace FasdDesktopUi.Basics.UserControls
         private ObservableCollection<HierarchicalSelectionItem> categoryHierarchy = new ObservableCollection<HierarchicalSelectionItem>();
         private readonly Dictionary<string, HierarchicalSelectionItem> categoryLookup = new Dictionary<string, HierarchicalSelectionItem>(StringComparer.OrdinalIgnoreCase);
         private bool isCategoryLoading;
+        private Brush defaultCategoryBorderBrush;
+        private Brush defaultQuickTicketBorderBrush;
+        private readonly Brush validationErrorBrush = new SolidColorBrush(Colors.Red);
 
         public bool IsTicket
         {
@@ -230,7 +233,10 @@ namespace FasdDesktopUi.Basics.UserControls
         private static void OnSelectedCategoryChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
         {
             if (d is CloseCaseDialogWithTicket instance)
+            {
                 instance.LogSelectedCategoryChanged(e.NewValue as HierarchicalSelectionItem);
+                instance.ValidateProperty("SelectedCategory");
+            }
         }
 
         #endregion
@@ -403,9 +409,11 @@ namespace FasdDesktopUi.Basics.UserControls
                 me.UpdateTicketComponentVisibility();
                 await me.InitializeCategorySelectionAsync();
                 await me.UpdateQuickCallsComboBoxAsync();
-            }
-            catch (Exception E)
-            {
+                me.ValidateProperty("SelectedCategory");
+                me.ValidateProperty("QuickTicketSelection");
+            }
+            catch (Exception E)
+            {
                 LogException(E);
             }
 
@@ -418,14 +426,18 @@ namespace FasdDesktopUi.Basics.UserControls
 
         private TicketCompletion parentWindow;
 
-        public CloseCaseDialogWithTicket()
-        {
-            InitializeComponent();
-            this.Unloaded += CloseCaseDialogWithTicket_Unloaded;
-            this.Loaded += CloseCaseDialogWithTicket_Loaded;
-
-            DependencyPropertyDescriptor dpd =
-                DependencyPropertyDescriptor.FromProperty(TextBlock.TextProperty, typeof(TextBlock));
+        public CloseCaseDialogWithTicket()
+        {
+            InitializeComponent();
+            this.Unloaded += CloseCaseDialogWithTicket_Unloaded;
+            this.Loaded += CloseCaseDialogWithTicket_Loaded;
+            defaultCategoryBorderBrush = CategorySelectionControl?.BorderBrush?.CloneCurrentValue();
+            defaultQuickTicketBorderBrush = QuickTicketSelection?.BorderBrush?.CloneCurrentValue();
+            if (validationErrorBrush is Freezable freezableBrush && freezableBrush.CanFreeze)
+                freezableBrush.Freeze();
+
+            DependencyPropertyDescriptor dpd =
+                DependencyPropertyDescriptor.FromProperty(TextBlock.TextProperty, typeof(TextBlock));
 
             dpd?.AddValueChanged(CaseNotesPreview, TicketCaseNotesTextBlock_TextChanged);
 
@@ -444,10 +456,12 @@ namespace FasdDesktopUi.Basics.UserControls
             parentWindow.SetButtonStateYes(false, "Initial gesperrt.");
             parentWindow.SetButtonStateNo(true, cMultiLanguageSupport.GetItem("Dialog.CloseCase.Cancel"));
 
-            ValidateProperty("TicketSummaryTextBox");
-            ValidateProperty("TicketStatusCombobox");
-            ValidateProperty("CaseNotesPreview");
-        }
+            ValidateProperty("TicketSummaryTextBox");
+            ValidateProperty("TicketStatusCombobox");
+            ValidateProperty("CaseNotesPreview");
+            ValidateProperty("SelectedCategory");
+            ValidateProperty("QuickTicketSelection");
+        }
         private void CloseCaseDialogWithTicket_Unloaded(object sender, RoutedEventArgs e)
         {
             Window parentWindow = Window.GetWindow(this);
@@ -937,6 +951,7 @@ namespace FasdDesktopUi.Basics.UserControls
             finally
             {
                 isCategoryLoading = false;
+                ValidateProperty("SelectedCategory");
             }
         }
 
@@ -1125,13 +1140,14 @@ namespace FasdDesktopUi.Basics.UserControls
                     });
                 }
 
-                QuickTicketSelection.ItemsSource = quickCallListe;
-
-                QuickTicketSelection.SelectedItem = quickCallListe
-                    .FirstOrDefault(x => x.ID == "7bbe64e2-94d0-ee11-4285-00155d010a04");
-            }
-            catch (Exception e)
-            {
+                QuickTicketSelection.ItemsSource = quickCallListe;
+
+                QuickTicketSelection.SelectedItem = quickCallListe
+                    .FirstOrDefault(x => x.ID == "7bbe64e2-94d0-ee11-4285-00155d010a04");
+                ValidateProperty("QuickTicketSelection");
+            }
+            catch (Exception e)
+            {
                 LogException(e);
             }
         }
@@ -1980,10 +1996,10 @@ namespace FasdDesktopUi.Basics.UserControls
                     }
                     break;
 
-                case "TicketStatusCombobox":
-                    validateComboboxNotEmpty(TicketStatusCombobox);
-                    if (!(TicketStatusCombobox.SelectedItem is ComboBoxItem a))
-                        break;
+                case "TicketStatusCombobox":
+                    validateComboboxNotEmpty(TicketStatusCombobox);
+                    if (!(TicketStatusCombobox.SelectedItem is ComboBoxItem a))
+                        break;
 
                     enumTicketStatus currenTicketStatus = enumTicketStatus.Unknown;
                     var currentTicketActivityType = SelectedTicket?.Infos.FirstOrDefault(x => x.Key == "ActivityType").Value;
@@ -2041,12 +2057,47 @@ namespace FasdDesktopUi.Basics.UserControls
                     else
                     {
                         ShowAssetWarningTicketAction = false;
-                    }
-
-                    break;
-            }
-
-            return new List<string>(_errors.Values);
+                    }
+
+                    break;
+                case "SelectedCategory":
+                    bool categoryIsVisible = CategorySelectionControl?.IsVisible ?? false;
+                    bool categoryHasError = categoryIsVisible && SelectedCategory == null;
+                    UpdateCategoryValidationVisualState(categoryHasError);
+
+                    if (categoryHasError)
+                    {
+                        if (!_errors.ContainsKey(propertyName))
+                            _errors.Add(propertyName, cMultiLanguageSupport.GetItem("Dialog.CloseCase.ValidationErrorCategoryEmpty"));
+                    }
+                    else
+                    {
+                        if (_errors.ContainsKey(propertyName))
+                            _errors.Remove(propertyName);
+                    }
+
+                    break;
+                case "QuickTicketSelection":
+                    bool quickCallIsVisible = QuickTicketSelection?.IsVisible ?? false;
+                    bool quickCallSelected = QuickTicketSelection?.SelectedItem is QuickCallEntry selectedQuickCall && !string.IsNullOrWhiteSpace(selectedQuickCall.ID);
+                    bool quickCallHasError = quickCallIsVisible && !quickCallSelected;
+                    UpdateQuickTicketValidationVisualState(quickCallHasError);
+
+                    if (quickCallHasError)
+                    {
+                        if (!_errors.ContainsKey(propertyName))
+                            _errors.Add(propertyName, cMultiLanguageSupport.GetItem("Dialog.CloseCase.ValidationErrorQuickCallEmpty"));
+                    }
+                    else
+                    {
+                        if (_errors.ContainsKey(propertyName))
+                            _errors.Remove(propertyName);
+                    }
+
+                    break;
+            }
+
+            return new List<string>(_errors.Values);
         }
 
 
@@ -2388,9 +2439,9 @@ namespace FasdDesktopUi.Basics.UserControls
         }
 
 
-        private static void setTextboxErrorState(object sender, bool hasError)
-        {
-            if (sender is TextBox textBox)
+        private static void setTextboxErrorState(object sender, bool hasError)
+        {
+            if (sender is TextBox textBox)
             {
                 // Überprüfe den Inhalt und setze die Hintergrundfarbe entsprechend
                 if (hasError)
@@ -2403,9 +2454,35 @@ namespace FasdDesktopUi.Basics.UserControls
                     // Setze die ursprüngliche Hintergrundfarbe zurück, wenn die Validierung erfolgreich ist
                     textBox.BorderBrush = (SolidColorBrush)new BrushConverter().ConvertFromString("#DEE2E6");
                 }
-            }
-        }
-
+            }
+        }
+
+        private void UpdateCategoryValidationVisualState(bool hasError)
+        {
+            if (CategorySelectionControl == null)
+                return;
+
+            if (defaultCategoryBorderBrush == null)
+                defaultCategoryBorderBrush = CategorySelectionControl.BorderBrush?.CloneCurrentValue();
+
+            CategorySelectionControl.BorderBrush = hasError
+                ? validationErrorBrush
+                : defaultCategoryBorderBrush;
+        }
+
+        private void UpdateQuickTicketValidationVisualState(bool hasError)
+        {
+            if (QuickTicketSelection == null)
+                return;
+
+            if (defaultQuickTicketBorderBrush == null)
+                defaultQuickTicketBorderBrush = QuickTicketSelection.BorderBrush?.CloneCurrentValue();
+
+            QuickTicketSelection.BorderBrush = hasError
+                ? validationErrorBrush
+                : defaultQuickTicketBorderBrush;
+        }
+
 
 
         #region DropDown
@@ -2453,10 +2530,15 @@ namespace FasdDesktopUi.Basics.UserControls
             }
 
         }
-        private void ComputerSelection_SelectionChanged(object sender, SelectionChangedEventArgs e)
-        {
-            SelectedComputer = (cF4sdApiSearchResultRelation)ComputerSelection.SelectedItem;
-        }
+        private void ComputerSelection_SelectionChanged(object sender, SelectionChangedEventArgs e)
+        {
+            SelectedComputer = (cF4sdApiSearchResultRelation)ComputerSelection.SelectedItem;
+        }
+
+        private void QuickTicketSelection_SelectionChanged(object sender, SelectionChangedEventArgs e)
+        {
+            ValidateProperty("QuickTicketSelection");
+        }
 
         private void TransferCaseNotesCheck_Unchecked(object sender, RoutedEventArgs e)
         {
diff --git a/FasdDesktopUi/Config/LanguageDefinitions.xml b/FasdDesktopUi/Config/LanguageDefinitions.xml
index 3e862d3..2094394 100644
--- a/FasdDesktopUi/Config/LanguageDefinitions.xml
+++ b/FasdDesktopUi/Config/LanguageDefinitions.xml
@@ -1578,13 +1578,21 @@
     <Language Lang="DE">Fehler: </Language>
   </UIItem>
 
-  <UIItem Name="Dialog.CloseCase.ValidationErrorSummaryEmpty">
-    <Language Lang="EN">Fill summary</Language>
-    <Language Lang="DE">Zusammenfassung angeben</Language>
-  </UIItem>
-
-  <UIItem Name="Dialog.CloseCase.ValidationErrorSolutionEmpty">
-    <Language Lang="EN">Fill solution</Language>
+  <UIItem Name="Dialog.CloseCase.ValidationErrorSummaryEmpty">
+    <Language Lang="EN">Fill summary</Language>
+    <Language Lang="DE">Zusammenfassung angeben</Language>
+  </UIItem>
+  <UIItem Name="Dialog.CloseCase.ValidationErrorCategoryEmpty">
+    <Language Lang="EN">Select a category</Language>
+    <Language Lang="DE">Kategorie auswählen</Language>
+  </UIItem>
+  <UIItem Name="Dialog.CloseCase.ValidationErrorQuickCallEmpty">
+    <Language Lang="EN">Select a quickcall template</Language>
+    <Language Lang="DE">Quickcall auswählen</Language>
+  </UIItem>
+
+  <UIItem Name="Dialog.CloseCase.ValidationErrorSolutionEmpty">
+    <Language Lang="EN">Fill solution</Language>
     <Language Lang="DE">Lösung angeben</Language>
   </UIItem>