Req help regarding Bug which was there in 2.6.3 but not in 2

[IE SPECIFIC IE7]
HI there was bug in 2.6.3 but its not in 2.6.4.
In demo site select option06 which is plugin.If you place following code in source and test in editor, you will find that after selecting "Table Properties", will have caption in version 2.6.4 but not in version 2.6.3.What kind of changes are done ,please help me
Copy paste following code in source ::
<p>&nbsp;</p>
<fieldset>
<table cellspacing="1" cellpadding="1" width="200" border="1">
<caption>adada</caption>
<tbody>
<tr>
<td>&nbsp;[[sasa]]</td>
<td>&nbsp;</td>
</tr>
<tr>
<td>&nbsp;</td>
<td>&nbsp;</td>
</tr>
<tr>
<td>&nbsp;</td>
<td>&nbsp;</td>
</tr>
</tbody>
</table>
&nbsp;[[s2]]</fieldset>
<p>[[sqee]]</p>
<table height="40" cellspacing="1" cellpadding="1" width="200" border="1">
<caption>tableoutside</caption>
<tbody>
<tr>
<td>&nbsp;</td>
<td>&nbsp;</td>
</tr>
<tr>
<td>&nbsp;</td>
<td>&nbsp;</td>
</tr>
<tr>
<td>&nbsp;</td>
<td>&nbsp;</td>
</tr>
</tbody>
</table>
<p>&nbsp;</p>

Thanks
Sankalp