Finder doesn't get focus

There is no setting for that. What you can do is first reboot your Mac. If that doesn't work, you can create a temperary new user and log in as that. Then, use it for a while and see if it has the issue. If so, it may be a system issue and you may need to reinstall OS X.

If it doesn't have the issue, go back to your user and go to your user library folder. If you are in Lion, click the go menu in finder and hold the option key down and click library. Go to your preferences folder and find com.apple.finder.plist and delete it. Then log out and log back in and see if that worked.

 

Then reset your system cache. Run the command in /Applications/Utilities/Terminal:

Code:

/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -kill -r -domain local -domain system -domain user

. No sudo required and let it run until you get another Terminal prompt (make sure you have all finder windows closed at the time).

After running that command hold down on the 'option' key while clicking on the Finder's dock icon and choose 'Relaunch'.

Hopefully this will fix you problem, good luck.

 

I have had this issue. The usual culprit is an application I have open that has stopped responding. Force Quitting the offending application restores harmony.