LehrerApp/LehrerApp.Desktop/Views/Workload/AddEditWorkTaskDialog.axaml

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:vm="clr-namespace:LehrerApp.Desktop.ViewModels.Workload"
        xmlns:models="clr-namespace:LehrerApp.Core.Models;assembly=LehrerApp.Core"
        x:Class="LehrerApp.Desktop.Views.Workload.AddEditWorkTaskDialog"
        x:DataType="vm:AddEditWorkTaskDialogViewModel"
        Title="{Binding DialogTitle}"
        Width="420" Height="480" MinWidth="380" MinHeight="420"
        CanResize="True" WindowStartupLocation="CenterOwner">

  <Grid RowDefinitions="*,Auto" Margin="24">
    <ScrollViewer Grid.Row="0">
      <StackPanel Spacing="14" Margin="0,0,12,0">
        <TextBlock Text="{Binding DialogTitle}" Classes="dialogtitle"/>

        <StackPanel Spacing="4">
          <TextBlock Text="Titel *" FontSize="12" Opacity="0.7"/>
          <TextBox Text="{Binding Title}" PlaceholderText="z.B. Klausur 8a korrigieren"/>
          <TextBlock Text="{Binding TitleError}" Foreground="Red" FontSize="11"
                     IsVisible="{Binding TitleError, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"/>
        </StackPanel>

        <CheckBox Content="🔔 Nur Erinnerung (kein Zeitbezug, läuft nicht in die Zeiterfassung ein)"
                  IsChecked="{Binding IsReminder}"/>

        <Grid ColumnDefinitions="*,8,*">
          <StackPanel Grid.Column="0" Spacing="4">
            <TextBlock Text="Kategorie *" FontSize="12" Opacity="0.7"/>
            <ComboBox ItemsSource="{Binding CategoryOptions}" SelectedItem="{Binding SelectedCategory}"
                      HorizontalAlignment="Stretch"/>
          </StackPanel>
          <StackPanel Grid.Column="2" Spacing="4">
            <TextBlock Text="Gruppe (optional)" FontSize="12" Opacity="0.7"/>
            <ComboBox ItemsSource="{Binding Groups}" SelectedItem="{Binding SelectedGroup}"
                      HorizontalAlignment="Stretch" PlaceholderText="Keine Gruppe">
              <ComboBox.ItemTemplate>
                <DataTemplate x:DataType="models:LearningGroup">
                  <TextBlock Text="{Binding Name}"/>
                </DataTemplate>
              </ComboBox.ItemTemplate>
            </ComboBox>
          </StackPanel>
        </Grid>

        <Grid ColumnDefinitions="*,8,*">
          <StackPanel Grid.Column="0" Spacing="4">
            <TextBlock Text="Fällig am (optional)" FontSize="12" Opacity="0.7"/>
            <TextBox Text="{Binding DueDateText}" PlaceholderText="TT.MM.JJJJ"/>
            <TextBlock Text="{Binding DueDateError}" Foreground="Red" FontSize="11"
                       IsVisible="{Binding DueDateError, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"/>
          </StackPanel>
          <StackPanel Grid.Column="2" Spacing="4" IsVisible="{Binding !IsReminder}">
            <TextBlock Text="Geschätzte Dauer in min (optional)" FontSize="12" Opacity="0.7"/>
            <TextBox Text="{Binding EstimatedMinutesText}" PlaceholderText="z.B. 90"/>
            <TextBlock Text="{Binding EstimatedMinutesError}" Foreground="Red" FontSize="11"
                       IsVisible="{Binding EstimatedMinutesError, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"/>
          </StackPanel>
        </Grid>

        <Grid ColumnDefinitions="*,8,*">
          <StackPanel Grid.Column="0" Spacing="4">
            <TextBlock Text="Wiederholung" FontSize="12" Opacity="0.7"
                       ToolTip.Tip="Beim Abschließen wird automatisch die nächste Instanz mit neuem Fälligkeitsdatum angelegt. Braucht ein Fälligkeitsdatum als Ausgangspunkt."/>
            <ComboBox ItemsSource="{Binding RecurrenceOptions}" SelectedItem="{Binding SelectedRecurrence}"
                      HorizontalAlignment="Stretch"/>
          </StackPanel>
          <StackPanel Grid.Column="2" Spacing="4">
            <TextBlock Text="Priorität" FontSize="12" Opacity="0.7"/>
            <ComboBox ItemsSource="{Binding PriorityOptions}" SelectedItem="{Binding SelectedPriority}"
                      HorizontalAlignment="Stretch"/>
          </StackPanel>
        </Grid>

        <StackPanel Spacing="4">
          <TextBlock Text="Notizen (optional)" FontSize="12" Opacity="0.7"/>
          <TextBox Text="{Binding Notes}" AcceptsReturn="True" TextWrapping="Wrap" Height="80"/>
        </StackPanel>

        <StackPanel Spacing="4">
          <Grid ColumnDefinitions="*,Auto">
            <TextBlock Grid.Column="0" Text="Abhak-Liste (optional)" FontSize="12" Opacity="0.7"
                       VerticalAlignment="Center"/>
            <Button Grid.Column="1" Content="Aus Kursliste befüllen" FontSize="11" Padding="7,3"
                    Command="{Binding FillFromRosterCommand}" IsVisible="{Binding CanFillFromRoster}"/>
          </Grid>
          <ItemsControl ItemsSource="{Binding ChecklistItems}">
            <ItemsControl.ItemTemplate>
              <DataTemplate x:DataType="vm:ChecklistItemRow">
                <Grid ColumnDefinitions="Auto,*,Auto" Margin="0,2">
                  <CheckBox Grid.Column="0" IsChecked="{Binding IsDone}"/>
                  <TextBlock Grid.Column="1" Text="{Binding Label}" VerticalAlignment="Center"
                             TextTrimming="CharacterEllipsis"/>
                  <Button Grid.Column="2" Content="✕" FontSize="11" Padding="6,2"
                          Command="{Binding $parent[ItemsControl].((vm:AddEditWorkTaskDialogViewModel)DataContext).RemoveChecklistItemCommand}"
                          CommandParameter="{Binding}"/>
                </Grid>
              </DataTemplate>
            </ItemsControl.ItemTemplate>
          </ItemsControl>
          <Grid ColumnDefinitions="*,8,Auto">
            <TextBox Grid.Column="0" Text="{Binding NewChecklistItemText}" PlaceholderText="Eigener Punkt..."/>
            <Button Grid.Column="2" Content="+" Command="{Binding AddChecklistItemCommand}"/>
          </Grid>
        </StackPanel>
      </StackPanel>
    </ScrollViewer>

    <Grid Grid.Row="1" ColumnDefinitions="*,8,*" Margin="0,20,0,0">
      <Button Grid.Column="0" Content="Abbrechen" HorizontalAlignment="Stretch" Click="OnCancel"/>
      <Button Grid.Column="2" Content="Speichern" HorizontalAlignment="Stretch" Click="OnSave"/>
    </Grid>
  </Grid>
</Window>