Making your website work with Win XP SP2 might be interesting for all those sites out there currently employing dhtml hierarchical menu systems (fly outs).

Q: What does Internet Explorer consider a pop-up window?
Internet Explorer will attempt to block any window opened automatically from:

• A script, with the exception of createPopup().
• Modal and modeless dialogs.
• DHTML elements overlapping content on the page

(A popup that opens as a direct result of user action will not be blocked.)

Hmmmm...and are we really that concerned about this? Personally I can't stand flyouts --- but what else would be affected?

And then there's this:
"MS confirms that Internet Explorer in Longhorn will not support XHTML or SVG." (from Hixie's Natural Log) So apparently MS has given up (yet again) on standards complience. Well, I'm not too overly concerned about SVG but I think XHTML support should not be dropped. Ugh! Let's not have to relive the browser wars again.