Make the MessageBox display properly with multi-line content

Stylet/MessageBoxView.xaml

@@ -10,7 +10,6 @@
         ResizeMode="NoResize"
         SizeToContent="WidthAndHeight"
         FlowDirection="{Binding FlowDirection}"
-        WindowStartupLocation="CenterScreen"
         ShowInTaskbar="False"
         MinWidth="160" MaxWidth="485"
         x:Name="RootObject">
@@ -25,12 +24,24 @@
             <RowDefinition Height="50"/>
         </Grid.RowDefinitions>
 
-        <Image Grid.Row="0" Grid.Column="1" Margin="19,0,0,0" VerticalAlignment="Center"
+        <Image Grid.Row="0" Grid.Column="1"
                Source="{Binding ImageIcon, Converter={x:Static s:IconToBitmapSourceConverter.Instance}}"
                Visibility="{Binding ImageIcon, Converter={x:Static s:BoolToVisibilityConverter.Instance}}">
+            <Image.Style>
+                <Style TargetType="Image">
+                    <Setter Property="VerticalAlignment" Value="Center"/>
+                    <Setter Property="Margin" Value="19,0,0,0"/>
+                    <Style.Triggers>
+                        <DataTrigger Binding="{Binding TextIsMultiline}" Value="True">
+                            <Setter Property="VerticalAlignment" Value="Top"/>
+                            <Setter Property="Margin" Value="19,25,0,0"/>
+                        </DataTrigger>
+                    </Style.Triggers>
+                </Style>
+            </Image.Style>
         </Image>
 
-        <TextBlock Grid.Row="0" Grid.Column="2" Text="{Binding Text}" Margin="8,30,15,30" TextWrapping="Wrap" TextAlignment="{Binding TextAlignment}"/>
+        <TextBlock Grid.Row="0" Grid.Column="2" Text="{Binding Text}" Margin="8,25,15,30" TextWrapping="Wrap" TextAlignment="{Binding TextAlignment}"/>
 
         <Grid Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="3" Background="{DynamicResource {x:Static SystemColors.ControlBrushKey}}">
             <ItemsControl ItemsSource="{Binding ButtonList}"

Stylet/MessageBoxViewModel.cs

@@ -182,6 +182,14 @@ namespace Stylet
         /// </summary>
         public virtual string Text { get; protected set; }
 
+        /// <summary>
+        /// Gets a value indicating whether the Text contains many lines
+        /// </summary>
+        public virtual bool TextIsMultiline
+        {
+            get { return this.Text.Contains("\n"); }
+        }
+
         /// <summary>
         /// Gets or sets the icon which the user specified
         /// </summary>

StyletUnitTests/MessageBoxTests.cs

@@ -37,6 +37,16 @@ namespace StyletUnitTests
             Assert.AreEqual("this is the text", this.vm.Text);
         }
 
+        [Test]
+        public void DeterminesTextIsMultilineCorrectly()
+        {
+            this.vm.Setup("this is the text", null, MessageBoxButton.OK, System.Windows.MessageBoxImage.None, MessageBoxResult.None, MessageBoxResult.None, MessageBoxOptions.None, null);
+            Assert.IsFalse(this.vm.TextIsMultiline);
+
+            this.vm.Setup("hello\nworld", null, MessageBoxButton.OK, System.Windows.MessageBoxImage.None, MessageBoxResult.None, MessageBoxResult.None, MessageBoxOptions.None, null);
+            Assert.IsTrue(this.vm.TextIsMultiline);
+        }
+
         [Test]
         public void SetsTitleCorrectly()
         {