topbar.xml

<Template>
  <WidgetGroup>
    <ObjectName>Topbar</ObjectName>
    <Layout>vertical</Layout>
    <Size>0me,50f</Size>
    <Children>
      <WidgetGroup>
        <ObjectName>TabControls</ObjectName>
        <Layout>horizontal</Layout>
        <SizePolicy>me,me</SizePolicy>
        <Children>
          <Template src="skin:tab.xml">
            <SetVariable name="tab_name">Overview</SetVariable>
            <SetVariable name="config_key">overview</SetVariable>
          </Template>
          <Template src="skin:tab_library.xml">
            <SetVariable name="tab_name">Browse</SetVariable>
            <SetVariable name="config_key">library</SetVariable>
          </Template>
          <Template src="skin:tab.xml">
            <SetVariable name="tab_name">Sampler</SetVariable>
            <SetVariable name="config_key">samplers</SetVariable>
          </Template>
        </Children>
      </WidgetGroup>
    </Children>
  </WidgetGroup>
</Template>