Tabbed renderings dialog for Sitecore

SelectRendering.xml

<?xml version="1.0" encoding="utf-8" ?>
<control xmlns:def="Definition" xmlns="http://schemas.sitecore.net/Visual-Studio-Intellisense">
  <Sitecore.Shell.Applications.Dialogs.SelectRendering>
    <FormDialog ID="Dialog" Icon="Core/32x32/open_document.png" Header="Open Item"
      Text="Select the item that you wish to open. Then click the Open button." OKButton="Open">
      <Stylesheet Src="SelectItemWithThumbnails.css" DeviceDependant="true" />
      <Script Src="/sitecore/shell/Applications/Dialogs/SelectRendering/dialog.js" />
      <CodeBeside Type="Abbey.Web.Custom.Dialogs.CustomSelectRenderingForm, Abbey.Web"/>
      

      <DataContext ID="DataContext" Root="/"/>

      <GridPanel Width="100%" Height="100%">

        <GridPanel Width="100%" Height="100%" Columns="3" GridPanel.Height="100%" Style="table-layout:fixed">

          <Scrollbox Width="100%" ID="TreeviewContainer" Height="100%" Class="scScrollbox scFixSize scFixSize4" style="border-right: 2px solid #474747;" Background="white" Padding="0px" GridPanel.Width="200px" GridPanel.Height="100%">
            <TreeviewEx ID="Treeview" DataContext="DataContext" ShowRoot="true" Click="Treeview_Click" />
          </Scrollbox>

          <VSplitter ID="TreeSplitter" GridPanel.Class="scThinSplitter" Target="left" />

          <Scrollbox ID="Renderings" Width="100%" Height="100%" Class="scScrollbox scFixSize scFixSize4" Background="white" Padding="0px" GridPanel.Height="100%">
          </Scrollbox>
          
          <Tabstrip ID="Tabs" Width="895px" Height="100%" Background="white" Padding="0px" style="position:absolute; width:100%;top:0px"/>

        </GridPanel>

        <Border ID="PlaceHolderNameBorder" Visible="false" style="padding:12px 0px 0px 0px">
          <GridPanel Columns="3" Width="100%">
            <Literal Text="Add to Placeholder: " GridPanel.NoWrap="true" />
            <Space Width="4" />
            <Edit ID="PlaceholderName" Name="PlaceholderName" GridPanel.Width="100%" class="scQuirksBoxModel" Width="100%" />
          </GridPanel>
        </Border>

      </GridPanel>

      <Border ID="OpenPropertiesBorder" def:placeholder="Buttons" Visible="false" style="padding:0px 0px 8px 0px">
        <Checkbox ID="OpenProperties" Header="Open the Properties dialog box immediately." />
      </Border>
    </FormDialog>
  </Sitecore.Shell.Applications.Dialogs.SelectRendering>
</control>