<a:application xmlns:a="https://github.com/pylonide/pylon">
    <a:window
      id        = "winExtensionTemplate"
      title     = "Extension Template Window"
      center    = "true"
      modal     = "false"
      buttons   = "close"
      skin      = "bk-window"
      kbclose   = "true"
      class     = "relative"
      width     = "300">
        <a:vbox>
            <a:hbox padding="5" edge="10">
                Hello World!
            </a:hbox>
            <a:hbox pack="end" padding="5" edge="6 10 10">
                <a:button 
                  caption = "Close" 
                  skin    = "btn-default-css3"
                  onclick = "
                   require('ext/extension_template/extension_template').closeExtensionTemplateWindow();"
                 />
            </a:hbox>
        </a:vbox>
    </a:window>
</a:application>