minor fixes for dialog & imagebutton

Pilz.UI.AvaloniaUI/Dialogs/AvaloniaFlyoutBase.axaml

@@ -5,13 +5,19 @@
              xmlns:controls="https://git.pilzinsel64.de/pilz-framework/pilz"
              xmlns:dialogs="clr-namespace:Pilz.UI.AvaloniaUI.Dialogs"
              mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
+             HorizontalAlignment="Stretch"
+             VerticalAlignment="Stretch"
              x:Class="Pilz.UI.AvaloniaUI.Dialogs.AvaloniaFlyoutBase">
     
-    <StackPanel Orientation="Vertical">
+    <Grid
+        ColumnDefinitions="*"
+        RowDefinitions="Auto,*,Auto"
+        >
         
         <!-- StackPanel: Header -->
         <StackPanel
             x:Name="StackPanelHeader"
+            Grid.Row="0"
             Orientation="Horizontal"
             HorizontalAlignment="Stretch"
             Margin="3"
@@ -33,6 +39,7 @@
         
         <!-- Panel: Content -->
         <ContentPresenter
+            Grid.Row="1"
             HorizontalAlignment="Stretch"
             VerticalAlignment="Stretch"
             Margin="3"
@@ -42,6 +49,7 @@
         <!-- StackPanel: Footer -->
         <Grid
             x:Name="StackPanelFooter"
+            Grid.Row="2"
             RowDefinitions="Auto"
             ColumnDefinitions="*,Auto,Auto"
             HorizontalAlignment="Stretch"
@@ -74,5 +82,5 @@
                 Click="ButtonCancel_OnClick"
             />
         </Grid>
-    </StackPanel>
+    </Grid>
 </UserControl>