Vista - HTML format changing on it's own

I'm working in an DotNet 2003 web application. I build an html page
that looks something like this:

<td>
<fieldset>
<legend>Report:</legend>
....more html here...
</fieldset>
</td>
<td>
<asp:textbox id="txtName" Runat="server" />
</td>

periodically when I come back to this to make changes, it'll change to
look like this:

<td>
<fieldset>
<legend>
Report:</LEGEND>
....more html here...
</FIELDSET>
</TD>
<td><asp:textbox id="txtName" Runat="server"></asp:textBox></TD>


????
Why does it do this? Is there a way to make it stop? I find this very
hard to read.

Doug wrote:
I would hope that it did not capitalize the end tags, making them not match!

I believe these are all controlled under the "Text Editor" "HTML"
"Format" options panel. There is a tag specific option that controls
how each tag is reformatted. My understanding is the reformatting is
done by choosing to reformat the document on the "Edit" menu. I don't
know this to happen automatically, but perhaps it can.

--
Mike