ASP.NET ReportViewer IE hangs 100% CPU

Question

We've recently been experiencing an SSRS (SQL Server 2008) report displayed in an ASP.NET web application using the ReportViewer control (Microsoft.ReportViewer.WebForms, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a) hanging when rendering a report with over 100 rows and causing Internet Explorer (6, 7, 8) to use 100% (of one core) of CPU.

The report renders quickly in Firefox (and doesn't use high CPU).

Answer 1

The issue seemed to be caused by using the IE PNG Alpha fix (v2.0, by Angus Turnbull, http://www.twinhelix.com/).

We were using a cascading style sheet to apply the behaviour to all img and div tags:

img, div 
{ 
    behavior: url(script/iepngfix.htc) 
}

Applying the behaviour to only the images we required resulted in the SSRS reports rendering quickly again.