I want to disable the command bar, but then the outputs are printed to the bottom of the window. How can I define a small area in the bottom window that is not filled with text?

Insert this into your game (using code view)

 <object name="bar">
    <layer1><![CDATA[
        <div id="bar"><br><br><br>Test</div>
            ]]></layer1>
  </object>  
  <function name="InitUserInterface">
    x = bar.layer1
    JS.eval ("$('#txtCommandDiv').after('"+ x +"')")
  </function>