GWTcelltable scrollbar

I have a table with cellTable see the code bellow :

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE ui:UiBinder SYSTEM "http://dl.google.com/gwt/DTD/xhtml.ent">
<ui:UiBinder xmlns:ui="urn:ui:com.google.gwt.uibinder" xmlns:g="urn:import:com.google.gwt.user.client.ui" xmlns:c="urn:import:com.google.gwt.user.cellview.client"
 xmlns:b="urn:import:com.bv.partenaire.graphique.client.ui.button">
    <ui:with field='msg' type="com.bv.partenaire.web.client.resources.Messages" />
    <ui:style>
        .important {
            font-weight: bold;
        }
    </ui:style>             
                    
    <g:HTMLPanel>
        <div class="modelBandeau">
            <div class="divGauche">
            <div class="testClass" style="background-color: green;">
                <g:Label styleName="recherche">
                    <ui:text from="{msg.rechercher}" />
                </g:Label>
            </div>
            <div style="margin-left:10px;margin-top: 1px;">
                <g:TextBox ui:field="rechercheBox" />
            </div>
            </div>
        </div>
    
        <table cellspacing='0' cellpadding='0' style='width:100%'>
            <tr>
                <td valign='top'>                                       
                    <c:CellTable ui:field="valideursTable" styleName="cellTable"/>                  
                </td>
            </tr>
            <tr>
                <td align='center'>
                    <c:SimplePager pageSize="10" ui:field="pager" />
                </td>
            </tr>
        </table>
    
        
    </g:HTMLPanel>
</ui:UiBinder> 

the code works fine, my issue is when I have long data in my columns there is no horizontal Scrollbar

I tried to add <g:ScroolPanel> and <g:VerticalPanel> still doesn't work ?

tried to add also some css

table{
display: block;overflow-x: auto;white-space: nowrap;
}

I don't use the DataGrid

Any ideas ?

it works only with CSS, just add the code above and fixed width (950px) and the scrollbar will appear