How to prevent other table elements not to change its position while adding new content to some TD

You can find the problem in the link below:

www.yunuerenguzel.com.tr/deneme

My problem is that when I click to "see Application" link, all applications of the studens are displayed under that particular row. However when the invisible row content (table) become visible, columns of the outer table slightly move to the left or right handside depending on the browser. What causes this and how can I prevent this?

Note: there is no proble开发者_Python百科m in the first row if you are using Chrome.

Use a percentage for every td. Like :

<table style="width:100%">
<tr>
    <td style="width:"50%"></td>
    <td style="width:"50%"></td>
</tr>

</table>