ActiveViewIndex Not Working As Expected With 3 View

I am trying to use the ActiveViewIndex to switch between these 3 view.

I am able to go to my vPrivilage view, but not my vAddNew.

Can anyone please help me identify my issue? Thanks in advance.

This is my html code:

    <asp:MultiView ID="mv1" runat="server" ActiveViewIndex="0">
    <asp:View ID="vList" runat="server">
        <div>
            <span><%=Resources.Resource.Search %></span> <span><%=Resources.Resource.Designation %></span> :
                    <asp:TextBox ID="txtSearch" runat="server"></asp:TextBox>
            <asp:ImageButton ID="imgCancel" runat="server" CausesValidation="False"
                CommandName="Cancel" ImageAlign="Middle"
                ImageUrl="~/Images/ico_search_16.png" Width="20px" ToolTip="<%$ Resources:Resource, Search %> " />
        </div>
        <asp:GridView ID="gvSettings"
            runat="server"
            AutoGenerateColumns="False"
            DataKeyNames="designationId"
            DataSourceID="dsSettings"
            CssClass="gv"
            AllowSorting="True"
            AllowPaging="True"
            PageSize="50"
            Width="100%"
            ShowHeaderWhenEmpty="True"
            EmptyDataText="<%$ Resources:Resource, NoRecordFound %>">
            <SelectedRowStyle CssClass="sel" />
            <AlternatingRowStyle CssClass="alt" />
            <PagerStyle CssClass="pgr" />
            <Columns>
                <asp:TemplateField ItemStyle-Width="1%" HeaderText="#">
                    <ItemTemplate>
                        <%# Container.DataItemIndex + 1 %>.
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="<%$ Resources:Resource, Designation %> ">
                    <ItemTemplate>
                        <asp:Label ID="lblDesignation" runat="server" Text='<%# Bind("ShortDesc") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField ShowHeader="False">
                    <ItemTemplate>
                        <asp:ImageButton ID="imgPrivilage" runat="server" CausesValidation="False"
                            ImageAlign="Middle" ImageUrl="~/Images/ico_settings_16.png" Width="20px"
                            ToolTip="<%$ Resources:Resource, RolePrivilege %> "
                            OnClick="imgPrivilage_Click" />
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
        </asp:GridView>
        <asp:UpdatePanel ID="upAddNew" runat="server">
            <ContentTemplate>
                <asp:Button ID="btnAddnew" runat="server" Text="<%$ Resources:Resource, Add %>" OnClick="btnAddnew_Click" />
            </ContentTemplate>
            <Triggers>
                <asp:AsyncPostBackTrigger ControlID="btnAddNew" EventName="Click" />
            </Triggers>
        </asp:UpdatePanel>
    </asp:View>
    <asp:View ID="vAddNew" runat="server">
        <table class="ZebraTable">
            <tr>
                <td style="width: 10%"><span><%=Resources.Resource.ShortDesc %></span></td>
                <td>
                    <asp:TextBox ID="txtShortDesc" MaxLength="100" runat="server" Text='<%# Eval("ShortDesc") %>' />
                    <asp:RequiredFieldValidator ID="rfvShortDesc" runat="server" InitialValue="" ControlToValidate="txtShortDesc" CssClass="errorValidation" ErrorMessage="<%$ Resources:Resource, Required %>"></asp:RequiredFieldValidator>
                </td>
            </tr>
            <tr>
                <td><span><%=Resources.Resource.Description %></span></td>
                <td>
                    <asp:TextBox ID="txtDescription" MaxLength="200" runat="server" Text='<%# Eval("Description") %>' Width="80%" />
                </td>
            </tr>
        </table>
        <asp:Button ID="btnSave" runat="server" Text="<%$ Resources:Resource, Save %>" OnClick="btnSave_Click" />
        <asp:Button ID="btnCancel" runat="server" Text="<%$ Resources:Resource, Cancel %>" CausesValidation="false" OnClick="btnCancel_Click" />
    </asp:View>
    <asp:View ID="vPrivilege" runat="server">
        <div style="float: right; margin-top: 0px;">
            <asp:ImageButton ID="imgBack" ImageUrl="~/Images/close.png"
                Width="25" Height="25" ToolTip="<%$ Resources:Resource, Close %>"
                runat="server" OnClick="imgBack_Click" />
        </div>
        <div style="float: right; margin-top: 0px;">
            <asp:ImageButton ID="imgSave" ImageUrl="~/Images/save.png"
                Width="25" Height="25" ToolTip="<%$ Resources:Resource, Save %>"
                runat="server" OnClick="imgSave_Click" />
        </div>
        <uc1:rolePrivilage runat="server" ID="rolePrivilage" />
    </asp:View>
</asp:MultiView>

Backend Code:

    protected void InitializeText()
    {
        mv1.ActiveViewIndex = 0;
    }


    protected void imgPrivilage_Click(object sender, ImageClickEventArgs e)
    {
        GridViewRow row = (GridViewRow)((ImageButton)sender).Parent.Parent;
        if (row != null)
        {
            rolePrivilage.roleId = gvSettings.DataKeys[row.RowIndex].Value.ToString();
            rolePrivilage.roleDesc = string.Format("{0} | {1}",
                                                  rolePrivilage.roleId, ((Label)row.FindControl("lblDesignation")).Text);               
        }

        mv1.ActiveViewIndex = 2;
    }

    protected void btnAddnew_Click(object sender, EventArgs e)
    {
        mv1.ActiveViewIndex = 1;
    }

    protected void imgBack_Click(object sender, ImageClickEventArgs e)
    {
        mv1.ActiveViewIndex = 0;
    }

I have looked for many online resources, but the code looks the same as mine. So I am not really sure what have I mislooked. Thanks in advance!