ComboBoxBase.Select() replace old value

[teamsar]

Hi all,

Have you ever found this problem ? When i tried to select combo box, it was replaced old value with the new one , this is my code :

this.multiCmbRoles.Select("GR00001"); //=> Administrator
this.multiCmbRoles.Select("GR00004"); //=> Operator

Current Result


Expected result must be shown



This the code of combobox

<ext:MultiCombo 
                                        runat="server" 
                                        ID="multiCmbRoles" 
                                        SelectionMode="Checkbox" 
                                        Width="200px" 
                                        ForceSelection="true"
                                        QueryMode="Remote"
                                        TriggerAction="All"
                                        TypeAheadDelay="200"
                                        DisplayField="GroupName"
                                        Editable="false"
                                        TypeAhead="true"
                                        ValueField="GroupId">
                                        <Store>
                                            <ext:Store runat="server" ID="groupStore" AutoLoad="true">
                                                <Model>
                                                    <ext:Model runat="server" ID="model3" IDProperty="GroupId">
                                                        <Fields>
                                                            <ext:ModelField Name="GroupId" Type="String" Mapping="GroupId" />
                                                            <ext:ModelField Name="GroupName" Type="String" Mapping="GroupName" />
                                                        </Fields>
                                                    </ext:Model>
                                                </Model>
                                            </ext:Store>
                                        </Store>
                                        <Listeners>
                                            <Change Handler="#{hfPrivilege}.setValue(#{multiCmbRoles}.getValue());" />
                                        </Listeners>
                                    </ext:MultiCombo>

Any idea ?? I'm really need your help guys.. Please :( This problem has been consuming much time.. Thx