E' stata rilasciata una Hot-Fix per Visual Studio 2008 che risolve diversi problemi di performance per il designer web in particolare per l'html viewer.

Direttamente dal blog di Scott:

Hot Fix Details

You can download this hot-fix roll-up for free here (it is a 2.6MB download).  Below is a list of the issues it fixes:

HTML Source view performance

• Source editor freezes for a few seconds when typing in a page with a custom control that has more than two levels of sub-properties.
• “View Code” right-click context menu command takes a long time to appear with web application projects.
• Visual Studio has very slow behavior when opening large HTML documents.
• Visual Studio has responsiveness issues when working with big HTML files with certain markup.
• The Tab/Shift-Tab (Indent/Un-indent) operation is slow with large HTML selections.

Design view performance

• Slow typing in design view with certain page markup configurations.

HTML editing

• Quotes are not inserted after Class or CssClass attribute even when the option is enabled.
• Visual Studio crashes when ServiceReference element points back to the current web page.

JavaScript editing

• When opening a JavaScript file, colorization of the client script is sometimes delayed several seconds.
• JavaScript IntelliSense does not work if an empty string property is encountered before the current line of editing.
• JavaScript IntelliSense does not work when jQuery is used.

Web Site build performance

• Build is very slow when Bin folder contains large number of assemblies and .refresh files with web-site projects.

Importante leggere le note di installazione:

For more information on how to download and install the above patch, please read this blog post here.  In particular, if you are using Windows Vista with UAC enabled, make sure to extract the patch to a directory other than "c:\" (otherwise you'll see an access denied error).

To verify that this hot-fix patch successfully installed, launch VS 2008 and select the Help->About menu item.  Make sure that there is an entry that says ‘Hotfix for Microsoft Visual Studio Team System 2008 Team Suite – ENU (KB946581)’. 

If you ever want to remove the patch, go to Control Panel -> Add/Remove Programs and select “Hotfix for Microsoft Visual Studio 2008 – KB946581” under Microsoft Visual Studio 2008 (or Visual Web Developer Express 2008) and click “Remove".