SelectionMode multple does not work with checkbox

I want to select a row if clicks on a checkbox & if i click on checkbox it should select the row. There should be multiple selection with checkboxes & rows as well. Primefaces: 3.3 JSF: 2.1

<p:dataTable id="csrTable" var="assignedTask"
                                    value="#{worklistPage.assignedTasksList}" paginator="true"
                                    paginatorPosition="bottom" rows="25" rowKey="#{assignedTask.id}"
                                    selection="#{worklistPage.selectedTasks}"
                                    selectionMode="multiple"
                                    styleClass="selectedRow" border="0">
        <p:ajax event="rowSelect" listener="#{worklistPage.onRowSelect}" update=":form1" />
     <p:column selectionMode="multiple" style="width:16px;text-align:center"/>