Strange Problem With Asp.net ... Tabpanel / Gridview Moving Out Of Table Area?

I am facing a strange issue with my project ... when page is rendering my tabpanel/gridview is moving out of table area. To brief: I have declared a tabpanel inside table like

<table id="table1" border="1" runat="server" width="100%">
<tr><td>
<cc1:tabcontainer .....>
<cc1: tabpanel .......>
<gridview .............>
</gridview>
</cc1:tabpanel>
</cc1:tabcontainer>
</td></tr>
<table>

When page renders ... my tabpanel display going out of table area ... means it's half inside table and half outside table.

I thought maybe the problem is with tabpanel ... I removed the panel and just kept GridView inside table like below

<table id="table1" border="1" runat="server" width="100%">
<tr><td>
<gridview .............>
</gridview>
</td></tr>
<table>

But still Iam facing the same issue. Gridview rendering is moving out of the table width. I tried changing the table width and Gridview width but no luck.

It's even not the problem with CSS design ... cause Gridview in other pages are working fine.