My current client is switching from IE 6 to 8 for their primarily ExtJS web application. I've been working on debugging some IE8 issues and had a peculiar problem where tables were refusing to display. At first I thought this was due to some bad markup, but using the new Developer tools in IE8 revealed that the elements were, in fact, present in the HTML.

I tried forcing the table to show by setting some styles via CSS, thinking I might have a layout issue, but nothing worked. I started to get pretty worried that a style being set by ExtJS was causing the issue and didn't know how I could fix it. I decided to try viewing the page in IE's "Compatibility Mode", since I knew this page worked in IE6, before digging through ExtJS. Lo and behold, the table reappeared.