Toolwindwo without icon

I want to popup a wpf toolwindow as a dialog in my app.

I also want it to be themed like the rest of my app (Metro)

So I set windwo style to ToolWIndow

And added the Theme Chrome.

WIndow looks ok except there is a blank space for the icon.

Dont want it.

What am I doing wrong?

<Window x:Class="NDS.ApplicationFactory.MetaModel.Target.DotNet.PropertyEditors.AttributesDialog"
               xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
               xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
               xmlns:themes="http://schemas.actiprosoftware.com/winfx/xaml/themes"
               Width="300"
               Height="300"
               ResizeMode="CanResize"
               ShowInTaskbar="False"
               Topmost="True"
               Title="Attributes"
               WindowStartupLocation="CenterOwner"
              WindowStyle="ToolWindow">
  <themes:WindowChrome.Chrome>
        <themes:WindowChrome HasMaximizeButton="True"
                                                 HasMinimizeButton="False"
                                                 HasRestoreButton="True"
                                                  HasOuterGlow="False">
        </themes:WindowChrome>
  </themes:WindowChrome.Chrome>
</Window>