enable button click for focus in tabbed.
enable button click for focus in tabbed.

Note that this patch doesn't work with

Thu Dec 27 03:03:56 EST 2007  Spencer Janssen <sjanssen@cse.unl.edu>
  * Broadcast button events to all layouts, fix for issue #111

but this isn't a regression, since button events have never worked with
tabbed and this change.

darcs-hash:20080204010536-72aca-3e6f9c697f8e6e26931850d84b56b3f5de917f55

yzhou61/xmonad-contrib,yzhou61/xmonad-contrib,yzhou61/xmonad-contrib