Avant Browser 2011 Build 21

* [Add]Automatically switching rendering mode
* [Add]Localised installation interface
* [Add]Hide/Show New Tab and Split Tab button.
* [Add]Category drop down menu added when downloading videos
* [Add]Import/Export function to AD Blocker and Popup Blocker
* [Change]Keeping Bookmarks menu open during deleting items
* [Fix]Rendering problem with some sites
* [Fix]For the sites using Windows authentication,Autofill window kept popping up even though the option was disabled.
* [Fix]Some bookmarks added from IE can't open in Avant
* [Fix]Downloader:Downloading selected links by file extension didn't work
* [Fix]User Agent String didn't show Avant Browser on the system with IE9
* [Fix]Javascript Error didn't disappear after the error was fixed.
* [Fix]Focused url in the Address Bar drop down list was opened by mistake
* [Fix]Some minor problems
* [Fix]Downloader:Messy code problem with Romanian interface
* [Fix]Detached Tab may be closed automatically