reformatting comments help

I have an issue and it might be a simple fix, but when I insert inline comments and reformat the page, the comments sometimes get moved to the next line.
example:

before auto reformating.....


<div >

          <p>some content</p>

</div><!-- /container -->


after reformatting the page....

<div >

          <p>some content</p>

</div>
<!-- /container -->

As you can see the comment for the closing div tag gets moved to the next line. It does not happen all the time, but most of the time. Is there a fix? thanks.