Why is Preview excessively slow after upgrading to Lion? After upgrading to OS X Lion, I noticed that my preview app is now excessively slow, taking minutes to open a file instead of seconds, even when opening a local file. In addition, it is often unresponsive.

What is the cause of tis, and do I have to reinstall Lion to fix this issue? I'd rather not go through the whole process again if possible.
OptCmdQ worked for me on a new Macbook Pro i5 2.4Ghz

I can only presume that discarding the previous windows cleaned out something that was causing the app to run slowly.