When I wave with a window, all other windows minimize to the taskbar, why? [duplicate]

This feature is called Shake. Just wiggle a window vigorously to minimize all other windows. You can also just release the click on the window, then click again and waggle to undo this.

Disabling Shake entirely requires a registry edit:

1. Browse to the following key:

   HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\Explorer
   

   (the Explorer key may not be there by default, just create it)

2. Make a 32-bit DWORD called "NoWindowMinimizingShortcuts".

3. Set the value to 1.

It most certainly is a 'feature' of Windows 7 and it's called 'Aero Shake', more details can be found here: http://windows.microsoft.com/en-US/windows7/products/features/shake

And what you are describing is exactly how it works. Grab the title bar of any window, give it a shake and everything else drops to the task bar.

To disable Shake you'll need to use either the Group Policy editor or do some registry tweaking as outlined here:

http://www.askvg.com/how-to-disable-aero-shake-in-windows-7/