fix some UI issues

src/AddIns/Debugger/Debugger.AddIn/Pads/ParallelPad/DrawSurface.xaml.cs

@@ -36,9 +36,11 @@ namespace Debugger.AddIn.Pads.ParallelPad
 		
 			if (graph == null)
 				this.ParallelStacksLayout.CancelLayout();
-			else
+			else {
+				this.ParallelStacksLayout.Relayout();
 				this.ParallelStacksLayout.Relayout();
 			}
+		}
 		
 		public bool IsZoomControlVisible {
 			get { return ZoomControl.Visibility == Visibility.Visible; }

src/AddIns/Debugger/Debugger.AddIn/Pads/ParallelPad/ThreadStack.xaml

@@ -4,6 +4,13 @@
 	Width="Auto"
 	Height="Auto"
 	Background="Transparent">
+	<UserControl.Resources>
+		<LinearGradientBrush x:Key="RowBackground" StartPoint="0.5,0" EndPoint="0.5,1">
+			<GradientStop Color="#F7F7F7" Offset="0.2"/>
+			<GradientStop Color="#EAEAEA" Offset=".5"/>
+			<GradientStop Color="#E5E5E5" Offset=".8"/>
+		</LinearGradientBrush>
+	</UserControl.Resources>
 	<Border
 		x:Name="BorderParent"
 		BorderBrush="Black"
@@ -85,7 +92,7 @@
 						<Setter Property="Background" Value="White"></Setter>
 						<Style.Triggers>
 							<Trigger Property="IsMouseOver" Value="True">
-                                <Setter Property="Background" Value="LightGray" />
+								<Setter Property="Background" Value="{StaticResource RowBackground}" />
 							</Trigger>
 						</Style.Triggers>
 					</Style>

src/AddIns/Debugger/Debugger.AddIn/Pads/ParallelPad/ThreadStack.xaml.cs

@@ -151,9 +151,6 @@ namespace Debugger.AddIn.Pads.ParallelPad
 				if (row != null)
 				{
 					datagrid.SelectedItem = row.DataContext;
-					if (toolTip.IsOpen)
-						toolTip.IsOpen = false;
-					toolTip.IsOpen = true;
 					e.Handled = true;
 				}
 			}