Focus Follows Mouse or Sloppy Focus on Mac OS X

"The fundamental problem with sloppy focus on the Mac is that the menu bar is always associated with the currently focused application; if you had sloppy focus, accessing the menu bar for a specific application would be supremely difficult.

Having said that, Zooom/2 does what you want, in addition to providing equivalents to the open-source window manager features for ctrl+click moving & resizing of windows."

"Steve Yegge over at his blog claims that focus follow mouse with no autoraise isn't going to happen on OS X anytime soon:

http://steve-yegge.blogspot.com/2008/04/settling-osx-focus-follows-mouse-debate.html

Since ALL OS X utilities out there that promise ""focus follows mouse"" do autoraise, I think Steve Yegge is sadly right."

There should be no problem with doing focus-follows-mouse without autoraise across all applications, as the Terminal example and command-click prove, but you'd need to inject code into running applications via mach_inject or similar. You'd essentially write an "input manager" that redirects the keystrokes/clicks any time the mouse enters a textbox/button. Any click that doesn't hit a button raises the window. And command-click only raises the window.

"The free, open-source Amethyst Mac app is an alternative to Zooom and Mondomouse (Whose links above seem to be broken).
You can download Amethyst here: github.com/ianyh/Amethyst"