<asp:table runat="server" ID="mainTable" Width="100%" Height="100%" BorderColor="Red" BorderWidth="20px" BorderStyle="Solid">
<asp:TableRow runat="server" ID="mainRow" Width="100%" Height="100%" BorderColor="Purple" BorderWidth="20px" BorderStyle="Solid">
<asp:TableCell runat="server" ID="maincell" Width="100%" Height="100%" BorderColor="AliceBlue" BorderWidth="20px" BorderStyle="Solid">
<asp:Panel runat="server" ID="mainpanel" Width="100px" Height="100px" BackColor="Gainsboro"></asp:Panel>
</asp:TableCell>
</asp:TableRow>
</asp:table>
Why does the tablerow is not shown?
I can see only a frame of RED, inside it a blue frame and inside it grey panel, where is the purple frame (the table row) between the red table and the blue cell?
It because the row color is overridden by the cells. A table cell is a part of table row only.