第三方控件UltraWebTree 的使用

<ignav:UltraWebTree id="FunctionTreeList" runat="server" TargetFrame="pagemain" JavaScriptFileNameCommon="../JS/ig_shared.js"
JavaScriptFilename="../JS/ig_webtree.js" ImageDirectory="../Images/" SingleBranchExpand="True" AutoPostBack="false"
ExpandOnClick="True" Font-Names="Microsoft Sans Serif" Font-Size="9pt" DefaultImage="ig_treeFolder.gif"
DefaultSelectedImage="ig_treeFolderOpen.gif" CollapseImage="ig_treeMinus.gif" ExpandImage="ig_treePlus.gif"
Cursor="Hand" Indentation="20" WebTreeTarget="ClassicTree">
<LeafNodeStyle ForeColor="White"></LeafNodeStyle>
<IslandStyle Cursor="Hand"></IslandStyle>
<HoverNodeStyle ForeColor="Yellow"></HoverNodeStyle>
<SelectedNodeStyle Cursor="Hand" ForeColor="Yellow" BackColor="#2F90CF">
<Padding Bottom="1px" Left="2px" Top="1px" Right="2px"></Padding>
</SelectedNodeStyle>
            <ClientSideEvents DragStart="" Drag="" Drop="" DragEnd="" DragEnter="" DragLeave="" 
                DragOver="" AfterBeginNodeEdit="" AfterEndNodeEdit="" AfterNodeSelectionChange="" AfterNodeUpdate="" 
                BeforeBeginNodeEdit="" BeforeEndNodeEdit="" BeforeNodeSelectionChange="" BeforeNodeUpdate="" NodeChecked="" 
                EditKeyDown="" EditKeyUp="" InitializeTree="" KeyDown="" KeyUp="" NodeClick="" 
                NodeCollapse="" NodeExpand="" DemandLoad="">
            </ClientSideEvents>内容</ignav:UltraWebTree>
其中点击收缩和展开的+ -号不管用了。请高手帮忙！