gtk2/demos/gtk-demo/menus.ui

<interface>
  <menu id="appmenu">
    <section>
      <item>
        <attribute name="label" translatable="yes">_New</attribute>
        <attribute name="action">app.new</attribute>
        <attribute name="accel">&lt;Primary&gt;n</attribute>
      </item>
      <item>
        <attribute name="label" translatable="yes">_Open</attribute>
        <attribute name="action">app.open</attribute>
      </item>
      <item>
        <attribute name="label" translatable="yes">_Save</attribute>
        <attribute name="action">app.save</attribute>
        <attribute name="accel">&lt;Primary&gt;s</attribute>
      </item>
      <item>
        <attribute name="label" translatable="yes">Save _As...</attribute>
        <attribute name="action">app.save-as</attribute>
        <attribute name="accel">&lt;Primary&gt;s</attribute>
      </item>
    </section>
    <section>
      <item>
        <attribute name="label" translatable="yes">_Quit</attribute>
        <attribute name="action">app.quit</attribute>
        <attribute name="accel">&lt;Primary&gt;q</attribute>
      </item>
    </section>
  </menu>
  <menu id="menubar">
    <submenu>
      <attribute name="label" translatable="yes">_Preferences</attribute>
      <section>
        <item>
          <attribute name="label" translatable="yes">_Prefer Dark Theme</attribute>
          <attribute name="action">app.dark</attribute>
        </item>
        <submenu>
          <attribute name="label" translatable="yes">_Color</attribute>
          <section>
            <item>
              <attribute name="label" translatable="yes">_Red</attribute>
              <attribute name="action">app.color</attribute>
              <attribute name="target">red</attribute>
              <attribute name="accel">&lt;Primary&gt;r</attribute>
            </item>
            <item>
              <attribute name="label" translatable="yes">_Green</attribute>
              <attribute name="action">app.color</attribute>
              <attribute name="target">green</attribute>
              <attribute name="accel">&lt;Primary&gt;g</attribute>
            </item>
            <item>
              <attribute name="label" translatable="yes">_Blue</attribute>
              <attribute name="action">app.color</attribute>
              <attribute name="target">blue</attribute>
              <attribute name="accel">&lt;Primary&gt;b</attribute>
            </item>
          </section>
        </submenu>
        <submenu>
          <attribute name="label" translatable="yes">_Shape</attribute>
          <section>
            <item>
              <attribute name="label" translatable="yes">_Square</attribute>
              <attribute name="action">win.shape</attribute>
              <attribute name="target">square</attribute>
              <attribute name="accel">&lt;Primary&gt;s</attribute>
            </item>
            <item>
              <attribute name="label" translatable="yes">_Rectangle</attribute>
              <attribute name="action">win.shape</attribute>
              <attribute name="target">rectangle</attribute>
              <attribute name="accel">&lt;Primary&gt;r</attribute>
            </item>
            <item>
              <attribute name="label" translatable="yes">_Oval</attribute>
              <attribute name="action">win.shape</attribute>
              <attribute name="target">oval</attribute>
              <attribute name="accel">&lt;Primary&gt;o</attribute>
            </item>
          </section>
        </submenu>
        <item>
          <attribute name="label" translatable="yes">_Bold</attribute>
          <attribute name="action">win.bold</attribute>
          <attribute name="accel">&lt;Primary&gt;&lt;Shift&gt;b</attribute>
        </item>
      </section>
    </submenu>
    <submenu>
      <attribute name="label" translatable="yes">_Help</attribute>
      <item>
        <attribute name="label" translatable="yes">_About</attribute>
        <attribute name="action">win.about</attribute>
        <attribute name="accel">&lt;Primary&gt;a</attribute>
      </item>
    </submenu>
  </menu>
</interface>