Click on email not heard (sometimes) after 10.7.2 update

I've noticed that since I did the recent Lion update to 10.7.2 that when I'm in Mail (the new interface, not classic) that SOMETIMES when I click on a email in my message list that it does not pop into the view pane. Sometimes it is heard, other times I have to click a second time. It is a random thing. I've tried all different combinations of the Mail window being active and inactive as well as other possibilities and it stays random.

Of course if I double-click too fast it opens the mail in its own window (which I don't want... I do most of my mail reading in the view pane.)

I don't seem to be having problems with clicking in any other application (Firefox, etc.) and the Magic Mouse has new batteries.

I've rebuilt mailboxes and done repair permissions and have done a shutdown.

Has anyone seen a similar occurrence of clicks on mail not being heard in Mail since this update?