2.3. Custom tool bar

This customization adds two buttons to the stock DocBook tool bar. See configuration element toolBar.

      .
  definition of macro-command docb.openInDefaultViewer
      .
      .

  <command name="docb.editDocument">
    <macro trace="false">
      <sequence>
        <get context="$implicitElement/@url" expression="resolve-uri(.)" />
        <command name="XXE.edit" parameter="%_" />
      </sequence>
    </macro>
  </command>

  <toolBar>
    <insert />
    <separator />
     <button toolTip="Open in Default Viewer [F2 o]" 
            icon="icons/openInDefaultViewer.gif">
      <command name="docb.openInDefaultViewer" />
    </button>
    <button toolTip="Edit Document [F2 e]" 
            icon="icons/editDocument.gif">
      <command name="docb.editDocument" />
    </button>
  </toolBar>

Note the insert attribute of the toolBar element which is used to insert all the tool bar buttons specified in the stock DocBook configuration before the new Open in Default Viewer button.