Double Letters & Skipped Pages - Launchpad

I have encountered this problem as well. An interesting thing is that when I invoke Launchpad, sometimes—not always—the search field is prepopulated with text I recently typed or text which was in my copy/paste buffer. I first realized this after I had typed my password to log in to discussions.apple.com in Chrome then invoked Launchpad and then saw in cleartext the password I had just typed! In Chrome, this same password was not visible on the screen since dots replaced the password characters. This problem could have accidentally exposed any password I had just typed to anyone who might have been looking over my shoulder at my screen or to any properly positioned security camera in a cafe or library. To confirm, I opened Sublime Text 2, opened a new tab, typed some new text, then invoked Launchpad, and again I saw the same new text I had just typed into Sublime Text 2.

I discovered a simple workaround that easily resolves the double letters problem: restart the Dock. I did this by opening Terminal and executing "killall Dock". The Dock application closes and restarts automatically. I then invoked Launchpad and found that my double character problem is gone, hopefully for good.

killall Dock also resolves the problem in which swiping in Launchpad from the first screen to the second screen skips the second screen and goes to the third screen. I had that problem as well and killall Dock resolved it.