I have an UltraWebGrid in an ascx file.
In the ascx.cs file, I have a spanning header
myGrid.Bands[0].Columns[0].Header.RowLayoutColumnInfo.OriginX = 0;
myGrid.Bands[0].Columns[0].Header.RowLayoutColumnInfo.SpanX = 2;
myGrid.Bands[0].Columns[0].Header.Caption = "Header Caption";
I then created an aspx page with an UltraWebTab control. With the (myGrid.ascx) control in the WebTab, the columns resize to different sizes. With the same control (myGrid.ascx) below the WebTab, the headers/columns stay the correct size.
<%@ Register Src="myGrid.ascx" TagName="myGrid" TagPrefix="uc1" %>
......
<body>
<form id="form1" runat="server">
<div>
<igtab:UltraWebTab ID="UltraWebTab1" runat="server" FixedLayout="True" Height="646px" Width="985px">
<Tabs>
<igtab:Tab AccessKey="G" Key="Grid" Text="Grid1">
<ContentTemplate>
<uc1:myGrid ID="Grid1" runat="server" />
</div>
</ContentTemplate>
</igtab:Tab>
</Tabs>
</igtab:UltraWebTab>
<uc1:myGrid ID="Grid2" runat="server" />
</body>