Mail does not respond to mouse clicks properly

Question

This bug in Mail started in Lion, and has continued (or possibly worsened in some instances) in Mountain Lion.  Has anybody heard of a fix?
Basically Mail acts like it is freezing, but in fact is not handling mouse clicks properly.
1) If Mail is "behind" another active app window, clicking in the content area of the Mail window will not activate the window until you click a SECOND time.
2) Once you get Mail to respond by clicking it the second time, if you click back and forth between it and the window in front (e.g. between safari and mail, the clicks DO register, but Mail acts as if the click position is offset from where you actually click.  The offset seems to vary and I haven't found a consistent link between the offset and where I click in mail or the other window, or the relative positions of the two windows.
3) When you try the 2) trick on elements that can scroll, you realise that as well as an offset, Mail is trying to "drag" instead of respond to a click, so the list of mail folders pulls and bounces back, or the list of mail scrolls, or sometimes if everything lines up, an image of an envelope appears and moves as if you are trying to drag an email from one place to another.
4) Clicking on the title/button/toolbar of Mail ALWAYS brings it to the front...
5) If you bring Mail to the front by repeatedly clicking on the content area (and yes, sometimes it takes more than one click...) and as the FIRST thing you do after activating the window, click one of the buttons in the toolbar (e.g. the trash or delete button), it will depress, and stay down, as if you have done a "press and hold" instead of a "click".  Clicking on the button again will complete the action, but clicking elsewhere in the title bar will release the button and the action will not occur, just as if you had held the mouse button down and dragged off the button before releasing, which is appropriate behaviour IF you had held the mouse button down in the first place...
6) If you activate Mail by clicking in the content area, then clicking a second time in the content area, then continue to single click around the content, it behaves as if it is one step behind you, responding as if the LAST click is the click you just made.  Interestingly the "button down state" seems to persist, because for instance clicking on a succession of emails will highlight each email in turn, but the content of the email on the right will not update with each click, only updating when you "break out of the cycle" with a double click or a title bar click.
These are all REPRODUCIBLE, even after a restart.
They ONLY happen in Mail.
I have tried mouse, track pad, turning off bluetooth, so I don't think these things are related.
SO...
I THINK that MAIL, since Lion, has an issue with its event handler, where MouseUp events are either lost or mishandled, so that clicks are being registered as drags, or the "button down" state is not updated or something...
With the above description I feel the Mail programming team should be able to track down the bug in minutes and fix it.
Apple - feel free to get in contact with me and I will let you access my machine via remote desktop or teamviewer or something to see the bug in action.
It is time to fix this annoying behaviour.
Message was edited by: jaffle
Worked out that 2 and 6 are related - the offset isn't an offset at all - it is the thing you last clicked on!

Answer 1

Okay, I tried deleting the Finder preferences first (along with a handful of other preference files that I knew were no longer needed), and it seemed to help--at first. But eventually, all the same problems started happening again, so I concluded that it was necessary to just start with a fresh (empty) preferences folder. As you know, this is a pain to deal with, but I limited my pain by moving all the old preferences files into a folder on the Desktop rather than simply deleting them. That way, I could just put back any missing preferences that were too hard to recreate. Restoring all of my preferences with new (uncorrupted) prefs files will be an ongoing process, but the good news is that this effort (so far) seems to have solved the problem. Mail is responding to all my clicks, even when I switch between different apps and different spaces.  :-)
Now that things are working correctly, I notice that when I switch between apps and/or spaces, the selected app (or the frontmost app in the new space) will show an active state for its window, whereas before, the selected app didn't update to show that it was active--it kept the inactive state for its window. I'm no expert, but it seems to me that this might have something to do with the windowserver process, so it might make sense for the next person who stumbles on this thread to start by deleting any preferences files that begin with com.apple.windowserver. Just a hunch, but it's worth starting there before you do a complete flush of all your preferences.
Thanks again for the help--hopefully this workaround will be persistent. Fingers crossed!