Combo box button inherit the element.style Css

Hi  i have a combo box which is present inside of the div which is hidden. when i click the image the div should appear with the combo box. But while i click the link the combox button height and width inhert from element.style. how to avoid this?

.tabelFilter
{
display:none;
}

$(".filterOpen").click(function () {
$(".tabelFilter").show("blind");
});

<a href="#" class="filterOpen"><img src="images/filter.png" alt="filter" align="top">

<div class="tabelFilter" >

<table style="width: 1070px" border="0" cellspacing="0" cellpadding="4" class="GridViewStyle">
<tr>
<td style="width: 100px; text-align: center">
<asp:ComboBox ID="FilterItemCategory" runat="server" Width="50" CssClass="demo"></asp:ComboBox>
</td>
<td style="width: 150px; text-align: left">
</td>
</tr>
</table>
</div>