L'élément tree est quasi similaire au html table. Les tableaux Tree supportent la multi-sélection (à l'aide des touches Ctrl et Maj).

Un tree simple.

<?xml-stylesheet href="css1.css" type="text/css" title="css1"?>
<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
align="vertical" >
     <tree>
          <treehead>
               <treerow>
                    <treecell><titledbutton value="AAA"/></treecell>
                    <treecell><titledbutton value="BBB"/></treecell>
               </treerow>
          </treehead>
          <treechildren>
               <treeitem>
                    <treerow>
                         <treecell><titledbutton value="ROW1"/></treecell>
                         <treecell><titledbutton value="1111"/></treecell>
                    </treerow>
               </treeitem>
               <treeitem>
                    <treerow>
                         <treecell><titledbutton value="ROW2"/></treecell>
                         <treecell><titledbutton value="2222"/></treecell>
                    </treerow>
               </treeitem>
               <treeitem>
                    <treerow>
                         <treecell><titledbutton value="ROW3"/></treecell>
                         <treecell><titledbutton value="3333"/></treecell>
                    </treerow>
               </treeitem>
               <treeitem>
                    <treerow>
                         <treecell><titledbutton value="ROW4"/></treecell>
                         <treecell><titledbutton value="4444"/></treecell>
                    </treerow>
               </treeitem>
          </treechildren>
     </tree>
</window>

xul2.xul

passer la valeur de l'attribut select à un treeitem à "true" selectionne cet item. Un treeitem peut contenir un treechildren qui en sera le fils. Les items définis dans ce cas créent donc un sous-arbre relevant du treeitem supérieur. Si ce treeitem n'a pas d'attribut open dont la valeur serait porté à "true", les items du sous-arbre ne sont pas affichés.

<?xml-stylesheet href="css1.css" type="text/css" title="css1"?>
<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
align="vertical" >
     <tree>
          <treehead>
               <treerow>
                    <treecell><titledbutton value="AAA"/></treecell>
                    <treecell><titledbutton value="BBB"/></treecell>
               </treerow>
          </treehead>
          <treechildren>
               <treeitem open="true">
                    <treerow>
                         <treecell><titledbutton value="Double click to colapse"/></treecell>
                         <treecell><titledbutton value="---"/></treecell>
                    </treerow>
                    <treechildren>
                         <treeitem>
                              <treerow>
                                   <treecell><titledbutton value="EXPAND1"/></treecell>
                                   <treecell><titledbutton value="aaaa"/></treecell>
                              </treerow>
                         </treeitem>
                         <treeitem>
                              <treerow>
                                   <treecell><titledbutton value="EXPAND2"/></treecell>
                                   <treecell><titledbutton value="bbbb"/></treecell>
                              </treerow>
                         </treeitem>
                    </treechildren>
               </treeitem>
               <treeitem>
                    <treerow>
                         <treecell><titledbutton value="Value"/></treecell>
                         <treecell><titledbutton value="bbbb"/></treecell>
                    </treerow>
               </treeitem>
               <treeitem selected="true">
                    <treerow>
                         <treecell><titledbutton value="Run"/></treecell>
                         <treecell><titledbutton value="qqqq"/></treecell>
                    </treerow>
               </treeitem>
          </treechildren>
     </tree>
</window>

css1.css

CSS

@import url(chrome://global/skin);
window {background-color: #EEFFEE}