Comment 135 for bug 729979

To make the bug easier to see and understand, make the animation slower:
"dconf write /com/canonical/unity/minimize-slow-duration 3000"
(You can undo this easily with "dconf reset /com/canonical/unity/minimize-slow-duration")
Now the animation should be slow enough to be able to interrupt it (meaning you are able to press the minimize button, and can move the mouse pointer faster to the launcher symbol and press it than the animated window is going there).
You can alternatively reproduce the effects shown in the linked video by moving the mouse pointer to the launcher and try to click the application instantly after the animation was initiated by pressing Strg + Alt + KP0 (numpad 0 key). The main point is, the bug seems to be quite randomly with default settings (most of the time it does not work, however there are situations when it works).
I found out, that you can reproduce the bug for sure if you apply the dconf setting mentioned above (you could also apply higher values). The slower the animation is, the more likely it is, that the bug happens.
The behaviour is shown in the following video:
http://ubuntuone.com/5xMF480diMFbN5np9rERcP

Now the very important part:

You can see, that the minimize animation ALWAYS works, when it was interrupted before (and the window is black, or without any content). But you have to consider, you are not allowed to shade/unshade, resize or click away from the window! This means doing only minimizing and unminimizing behind one another of the same window (without doing anything that makes the missing window content disappear), it works every second time.
If an window is opened, there is no way, that the animation works the first time minimizing, except you maximize it! This means you can always get the animation working if you maximize it before you press the minimize button (you have to maximize again even if the application is already maximized).
So to conclude there are two ways of always getting the animation work.

I have found an equivalent way to reproducing the bug (which could be relevant):
http://ubuntuone.com/16WmSevvitMlG8XfkfYzfE

(Note: For single windows in the video the ESC button was used to leave the spread without selecting the window. )
If you minimize a non fullscreen window (after you have opened it), click the spread view, leave it without selecting the minimized window and unminimize it, it gets the same condition as interrupting a window minimize.
This behaviour is not true for windows, that minimized correctly before, so the bug does not work for windows maximized an then minimised (last example in the video).
The behaviour shown in the second video is a consequence of the bug shown in the first video, so if you can reproduce the second bug this is also a proof for having the first bug.

The window content is missing when this bug appears, but if the window content is black or completely missing, depends if the window is transparent, or not.