The last change below may impact scripts that use the keyboard or mouse
hook. If you have any mission-critical scripts that rely on them, it is
recommended that they be re-tested or that you wait two weeks for any bugs
to get fixed.

Here are the changes:

Fixed inability to have lines consisting entirely of spaces and tabs in
continuation sections. [thanks JSLover]

Fixed hotkeys such as "LButton & LCtrl" to auto-install the mouse hook.
[thanks JSLover]

Added a dedicated thread to service the keyboard and mouse hooks. This
eliminates mouse/keyboard lag during long operations such as
UrlDownloadToFile. It also prevents keys from getting "stuck down". The new
thread consumes only 36 KB of memory and it exists only in scripts that use
the hooks.

http://www.autohotkey.com/download/