(This is technically an addendum to an earlier StackOverflow question I had posted, but my original post asked a different question which doesn't really cover this topic -- I don't want to edit my older question as I feel this is different enough to merit its own page)

While browsing my website in Firefox 3.5 (and only FF3.5), I come across a page with two radio buttons that have the following HTML code:

<input id="check1" type="radio" value="True" name="check" checked="checked"/>
<input id="check2" type="radio" value="False" name="check"/>

This page renders as expected, with 'check1' checked and 'check2' unchecked. When I then go to refresh the page by pressing Control + R, the two radio buttons render, but they are both unchecked even though the raw HTML code is the same (as above). If I do a cache-miss refresh (via Control + F5 or Control + Shift + R), the page returns back to the way you'd expect it.

This is not a problem in any other browser I've tried except FF3.5.

What is causing these radio buttons to be reset on a normal refresh? How can I avoid this?