Recent problem with UpdateProgress

[ESTAN]

Hi, I noticed since a couple of days that after a AsyncPostBack, the UpdateProgress doesn't disappear. It seems to happen only on IE, in Firefox it closes correctly after the AsyncPostBack. The updatepanel I am using used to work perfectly till recently, the website is still under development and I don't have a clue what is causing this problem. Anyone came across a similar problem? Or does anyone can help me finding the problem?. Thanks

[ESTAN]

Nevermind, I found out that I had tag that wasn't closed properly. Instead of <b>text<b> it should be <b>text</b> Is there a tool that can be used to find out this kind of errors?