treeview in update panel does not show styles such as background color,fore color, etc

i have changed the backcolor of my treeview nodes and selected nodes to different colors

wheni draw the treeview outside a updatepanel it shows the colors,

however if I draw it inside the updatepanel it does not show the colors

any help?

Try to post some of your codes here.I'd like to check this. Try to specify postback for the asp:TreeView.
Here are some sample codes about asp:TreeView for your reference.
<WebPart:webpartmanager id="WebPartManager1" runat="server" Personalization-Enabled="true"></WebPart:webpartmanager>
<WebPart:webpartzone id="WebPartZone1" runat="server" bordercolor="#CCCCCC" font-names="Verdana"
padding="6" width="169px">
<PartChromeStyle BackColor="#F7F6F3" ForeColor="White" BorderColor="#E2DED6" Font-Names="Verdana"></PartChromeStyle>
<MenuLabelHoverStyle ForeColor="#E2DED6"></MenuLabelHoverStyle>
<EmptyZoneTextStyle Font-Size="0.8em"></EmptyZoneTextStyle>
<MenuLabelStyle ForeColor="White"></MenuLabelStyle>
<MenuVerbHoverStyle BackColor="#F7F6F3" BorderStyle="Solid" ForeColor="#333333" BorderWidth="1px" BorderColor="#CCCCCC"></MenuVerbHoverStyle>
<HeaderStyle ForeColor="#CCCCCC" HorizontalAlign="Center" Font-Size="0.7em"></HeaderStyle>
<MenuVerbStyle BorderStyle="Solid" ForeColor="White" BorderWidth="1px" BorderColor="#5D7B9D"></MenuVerbStyle>
<PartStyle ForeColor="#333333" Font-Size="0.8em"></PartStyle>
<TitleBarVerbStyle ForeColor="White" Font-Size="0.6em" Font-Underline="False"></TitleBarVerbStyle>
<MenuPopupStyle BackColor="#5D7B9D" BorderWidth="1px" BorderColor="#CCCCCC" Font-Size="0.6em" Font-Names="Verdana"></MenuPopupStyle>
<PartTitleStyle BackColor="#5D7B9D" ForeColor="White" Font-Size="0.8em" Font-Bold="True"></PartTitleStyle>
<ZoneTemplate>
<asp:TextBox ID="tbWebPart" runat="server" Height="19px" Width="197px"></asp:TextBox>
<asp:UpdatePanel ID="upTree" runat="server" ChildrenAsTriggers="false" UpdateMode="Conditional">
<ContentTemplate>
<asp:DetailsView ID="DetailsView1" runat="server" Height="50px" Width="125px" AutoGenerateRows="False" DataSourceID="SqlDataSource1" AllowPaging="True" CellPadding="4" ForeColor="Black" GridLines="Vertical" BackColor="White" BorderColor="#DEDFDE" BorderStyle="None" BorderWidth="1px">
<Fields>
<asp:TemplateField>
<ItemTemplate>
<asp:TreeView ID="TreeView1" runat="server">
<Nodes>
<asp:TreeNode Text="File" Value="File">
<asp:TreeNode Text="New" Value="New"></asp:TreeNode>
<asp:TreeNode Text="Open" Value="Open"></asp:TreeNode>
<asp:TreeNode Text="Exit" Value="Exit"></asp:TreeNode>
</asp:TreeNode>
<asp:TreeNode Text="Edit" Value="Edit"></asp:TreeNode>
<asp:TreeNode Text="WebSite" Value="WebSite"></asp:TreeNode>
<asp:TreeNode Text="Build" Value="Build"></asp:TreeNode>
<asp:TreeNode Text="Debug" Value="Debug"></asp:TreeNode>
<asp:TreeNode Text="Format" Value="Format"></asp:TreeNode>
<asp:TreeNode Text="Help" Value="Help"></asp:TreeNode>
</Nodes>
</asp:TreeView>
</ItemTemplate>
<EditItemTemplate>
<asp:TreeView ID="TreeView2" runat="server" ShowCheckBoxes="All">
<Nodes>
<asp:TreeNode Text="File" Value="File">
<asp:TreeNode Text="New" Value="New"></asp:TreeNode>
<asp:TreeNode Text="Open" Value="Open"></asp:TreeNode>
<asp:TreeNode Text="Exit" Value="Exit"></asp:TreeNode>
</asp:TreeNode>
<asp:TreeNode Text="Edit" Value="Edit"></asp:TreeNode>
<asp:TreeNode Text="WebSite" Value="WebSite"></asp:TreeNode>
<asp:TreeNode Text="Build" Value="Build"></asp:TreeNode>
<asp:TreeNode Text="Debug" Value="Debug"></asp:TreeNode>
<asp:TreeNode Text="Format" Value="Format"></asp:TreeNode>
<asp:TreeNode Text="Help" Value="Help"></asp:TreeNode>
</Nodes>
</asp:TreeView>
</EditItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="ProductID" HeaderText="ProductID" InsertVisible="False"
ReadOnly="True" SortExpression="ProductID" />
<asp:BoundField DataField="ProductName" HeaderText="ProductName" SortExpression="ProductName" />
<asp:BoundField DataField="UnitPrice" HeaderText="UnitPrice" SortExpression="UnitPrice" />
<asp:CommandField ShowEditButton="True" />
</Fields>
<FooterStyle BackColor="#CCCC99" />
<EditRowStyle BackColor="#CE5D5A" Font-Bold="True" ForeColor="White" />
<RowStyle BackColor="#F7F7DE" />
<PagerStyle BackColor="#F7F7DE" ForeColor="Black" HorizontalAlign="Right" />
<HeaderStyle BackColor="#6B696B" Font-Bold="True" ForeColor="White" />
<AlternatingRowStyle BackColor="White" />
</asp:DetailsView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:ProductConnectionString %>"
SelectCommand="SELECT [ProductID], [ProductName], [UnitPrice] FROM [Product]" DeleteCommand="DELETE FROM [Product] WHERE [ProductID] = @.ProductID" InsertCommand="INSERT INTO [Product] ([ProductName], [UnitPrice]) VALUES (@.ProductName, @.UnitPrice)" UpdateCommand="UPDATE [Product] SET [ProductName] = @.ProductName, [UnitPrice] = @.UnitPrice WHERE [ProductID] = @.ProductID">
<DeleteParameters>
<asp:Parameter Name="ProductID" Type="Int32" />
</DeleteParameters>
<UpdateParameters>
<asp:Parameter Name="ProductName" Type="String" />
<asp:Parameter Name="UnitPrice" Type="Double" />
<asp:Parameter Name="ProductID" Type="Int32" />
</UpdateParameters>
<InsertParameters>
<asp:Parameter Name="ProductName" Type="String" />
<asp:Parameter Name="UnitPrice" Type="Double" />
</InsertParameters>
</asp:SqlDataSource>
</ContentTemplate>
<Triggers>
<asp:PostBackTrigger ControlID="DetailsView1" />
</Triggers>
</asp:UpdatePanel>
</ZoneTemplate>
</WebPart:webpartzone>
</div
Wish the above can help you.