As of HTML Editor 2010 SE and higher, the Preview tab uses Internet Explorer 8 (as long as it's installed on your system). Not only is this more modern, it also allows you to work with HTML5 and CSS3. However, if you'd rather use IE 7 in the Preview tab (which, for the record, we don't recommend), follow these instructions:

  1. Close the HTML Editor.
  2. Go to C:\Program Files\CoffeeCup Software, double-click PrevIE7.reg, and click Yes in the window that opens. This sets the Preview tab to IE 7.

If you would like to go back to using IE 8 in the Preview tab (which we highly recommend), follow these instructions:

  1. Close the HTML Editor.
  2. Go to C:\Program Files\CoffeeCup Software, double-click PrevIE8.reg, and click Yes in the window that opens. This sets the Preview tab to IE 8.

You can switch back and forth as many times as  you like. Just so you know, though, HTML5 and CSS3 are not fully compatible with IE7, so if you're designing in these languages, your best bet is to stick with IE8.