>>I use Chrome for all my web browsing including the UT. My only issue is that sometimes the UT shows up without any content and I'd have to refresh the page (sometimes several times) before I see the toolbar across the top from which I would then have to "Get all messages for today". The other issue is not being able to resize the panes (left side menu and treeview of messages). I can Ctrl+/-/0 to change the font size without any problems. I'm using Chrome 4.1.249.1064 (45376)
>
>I'm using FireFox right now and there is no sound when I get a new reply :(

A little while ago, Michel changed sound handling. The sound notifications are .WAV files; previously, you had to have a plugin installed on your browser that knew how to handle them. With FireFox, AFAIK the only plugin that can handle .WAVs natively is the Apple QuickTime plugin.

The change Michel made was to embed the Windows Media Player and explicitly call it to play the .WAV sounds. On the Account Setup page, where you can test your sounds, he uses this Javascript:

<script>
function PlayIt(tcFile)
{
   lcDiv=document.getElementById("PlayIt")
   lcDiv.innerHTML = '<embed type="application/x-mplayer2" ' +
    'pluginspage="http://www.microsoft.com/Windows/MediaPlayer/" ' +
    'name="MediaPlayer" src="' + tcFile + '.wav" autostart="true" showstatusbar="0" showcontrols="0" '+
    'showdisplay="0" volume="1" height="1" width="1" loop="false">'
}
</script>

The downside to this approach is this won't work on non-Windows OSs that don't have the Windows Media Player installed.

Are you running with Administrator privileges on your computer?

Is Windows Media Player installed and functional on your computer?

Can you hear the test sounds on the Account Setup page?

Are you running NoScript (you should be)? If so, have you set it to allow levelextreme.com and microsoft.com?

Do you have any other toolbars or addons in FireFox that block ads, popups etc.? Since some people might consider unsolicited sounds an annoyance, one of these might block sounds or other media plays by default.