How to Remove Duplicate Icons in Launchpad

To eliminate duplicate icons in Launchpad

1. Run  Terminal

2. Type  sudo rm ~/Library/Application\ Support/Dock/*.db
               to remove the problematic Launchpad database

3. Enter user password to permit change

4. Type  sudo killall Dock
_             
to recreate a new database

5. Exit  Terminal

Note:
A free app called Launchpad-control can do above resetting with just a few clicks.

How to Double-click-and-Drag in Lion

The Lion OSX no longer allows the action of Double-clicking the Title bar to Drag a Window by default.  To activate the function:

  • Go Universal Access under System Preferences
  • Enable Dragging under Trackpad Options

UPDATE:
In Mountain Lion, this Trackpad Option has been moved to Mouse & Trackpad under Accessibility category.