An annoying problem happens when using IE8 and you edit a Content Editor Web Part (CEWP) in SharePoint 2007 — it'll come up with an error saying it can not retrieve the properties. If you click OK, it lets you edit the CEWP, but when you go to Save, it'll fail. If you change your browser to use the Compatibility View for that site, you'll be able to save, but then it'll hang and timeout for that save. Very annoying.

The fix is to uncheck “Enable native XMLHTTP support” in Tools > Internet Options > Advanced tab.

A post with wonderful pictures on this issue is here.