IE Tab - an extension from Taiwan, features: Embedding Internet Explorer in tabs of Mozilla/Firefox...
This is a great tool for web developers, since you can easily see how your web page displayed in IE with just one click and then switch back to Firefox.
+ Added: A hidden pref "ietab.handleBookmarkURL" to decide whether
removes the IETAB's chrome:// string in bookmark dialog.
+ Fixed: Failed to load URL (starts with
"chrome://ietab/content/reloaded.html?url=") from addressbar.
+ Fixed: The alert(''); script on page load causes Firefox crash.
+ Fixed: The HTML code in "reloaded.html" causes 5 warnings show on
+ Fixed: Compatible with Fx3.0a3 and SeaMonkey.
+ Improved: Some descriptions in Options Dialog.
+ Add locale: id-ID (Indonesian)
Tools and Utilities
Product page: here