1⟩ Why do we see a dotted border around my SWF when using Firefox 3 on Windows and wmode transparent or opaque?
Firefox 3 on Windows using wmode transparent or opaque introduces a new default style for the object element; it treats it like an active link.
This Firefox implementation deviates from Firefox 3 on Mac, previous Firefox versions on Windows and the default style for the embed element, so it is therefore likely to be a Firefox bug.
The following style rule in the head of your web page should solve this issue:
<style type="text/css" media="screen">
object { outline:none; }
</style>