I found this on the Mac Store concerning WindowMizer.
If you have never used windowshading, you should try this. Of all the features that were lost in the move from System 9 to System X, this has been the most missed (hundreds of thousands of Google hits, most all in search of it), and for excellent reason. Try it for two weeks, and you’ll never want to be without it.
Windowshade was invented at the time of System 7 & incorporated into System 8. I know the history quite well because I was one of the people at Apple instrumental in getting it into System 8 having fallen in love with it myself. The boys from NeXT, having never used it, ripped it out in the move to OS X and replaced it with something provably inferior. WindowMizer puts windowshading back and does so in a way that avoids hacking into the operating system in the process. It's clean and will keep working with minimal upkeep. As others have pointed out, the functionality properly belongs in the OS itself, but Apple has always been and continues to be too stubborn to ever admit mistakes. In the meantime, this is the best that can be done without hacking the system. Other reviewers have pointed out problems, but the ones I’ve read can all be traced to poor documentation. I’m hoping what follows will straighten that out.
The first problem, having to have an application running all the time, is not really a problem. This is a tiny app, and we all have dozens, perhaps hundreds of processes running on our machines all the time. A problem only arises if the app doesn’t start up when the machine starts up. Normally, the WindowMizer preferences will set themselves to ensure that the app will launch automatically. If it doesn’t or your not sure, launch WindowMizer, open its Preferences, and ensure both options on the General tab are checked.
The rest of the problems arise when you try to minimize the window. First, you must ensure that the OS itself is not interpreting a double-click on the title bar to mean minimize-to-dock. The app will detect at start-up if that option is set to on, but, at the time of this writing, if you are using Mountain Lion, it will direct you to the wrong place to fix it: In Mountain Lion, you turn off that option in the Dock panel within System Preferences, not the General panel where it has historically been located.
Also when using Mountain Lion, at the time of this writing, you may discover the screen goes black when you double-click the title bar. Right now, the developer is instructing people in the FAQ to “Uncheck ‘Show animation when windows are windowmized/de-windowmized.’” In fact, you need to check that option, not uncheck it. (Or at least I had to, and I tried both ways several times.) Having the option on does have the unfortunate side effect of then displaying the window minimizing down to the dock at the same time as it is rolling up into the windowshade. It’s not nearly as disconcerting as having the screen go black, but it does take time.
This next hint is a definite must for Mountain Lion users who have to set animation to on and may be true for everyone: You can greatly decrease the time it takes to windowshade or unwindowshade a window by going to the Dock Preferences inside System Preferences and setting “Minimize Windows” to use the “Scale Effect.”
How it works: What the developer appears to be doing is quite clever and involves a lot of smoke and mirrors: He starts by asking the original app, using standard Apple-published methods, for the name, size, and location of the window that you have double-clicked on, then commands the original app to minimize it to the dock, again using a standard, Apple-published method. He then creates a new window within WindowMizer itself, giving it the identical name, the identical width, and the identical location as the one you were just using, but making it only as tall as the title bar. What you are now looking at is actually a new window within the WindowMizer app. (You’ll notice that the WindowMizer app has taken over the menu bar and the original window is sitting in the dock.) You can drag this stand-in window around as much as you wish just as you would have a real windowshaded window of yore. You can even resize it horizontally. When you later double-click the window in WindowMizer to restore it, the WindowMizer app communicates to the original app the new size and location, then tells it to redisplay the real window using those parameters, simultaneously taking down its own stand-in window in the process.
The advantage of the windowshade method is that the window largely gets out of your way while at the same time staying exactly where you had it. You don't have to go pawing through the dock to find it. Humans have been endowed with excellent spacial memories. That gets thrown away when documents are jumbled up in semi-random locations in a remote dock. If you need to see another document or the desktop below it, double-click, look, and double-click again and you're back. So much simpler. Need to open one of six text documents you've minimized? They all look identical in the dock. When they've been windowshaded, you can read each title perfectly. (Sometimes a word is worth a 1000 pictures.)
-Bruce Tognazzini, former Apple employee #66 and Apple's first human-computer interaction designer