Every time I run
gitk from a Mac OS X Terminal it opens in background.
In other words,
gitk is always shown behind the Terminal window.
gitk is the only tool manifesting this strange behavior.
gitx, for example, correctly opens in foreground.
I tried with 3 different macs, all with OS X Lion and all of them have this problem. Strangely, googling I wasn't able to find any info about this.
I found an old post about a guy with the same problem, but I guess it's not the same root cause since the post itself claims the bug was fixed in 2009.