Windows Confidential The Forgotten Hotkey
Originally, Windows came with just a single task-switching hotkey: Alt+Tab. And this is your grandfather's Alt+Tab—uphill both ways. The keystrokes may be the same, but the experience for the user was quite different. There was no fancy Alt+Tab window. Instead, each time you pressed the Tab key, a different program received focus. And minimized applications were not opened; you had to open them yourself after you released the Alt key.
The Alt+Tab functionality in Windows 2.0 took us closer to the Alt+Tab behavior we have today. Overlapping windows were maintained in a front-to-back list (known as the z-order), and each tap of the Tab key selected the next window, temporarily bringing it to the front so you could see it.
Alt+Tab in Windows Vista offers live thumbnails
When you released the Alt key, the window you selected was raised to the top of the window stack. For example, if your window stack consisted of windows A, B, C, and D, using Alt+Tab to select window C would result in a new window stack order of C, A, B, D.
In Windows 3.0, the Alt+Tab hotkey got a face-lift. The effect on the z-order remained unchanged, but there was a new interface for getting there. Instead of temporarily showing each window, it merely showed you the window's icon and title. Only when you selected a window was it brought to the top of the window stack.
This was known as Fast Alt+Tab. For a time, you could choose whether you wanted the new design or the old one, but the new design was so much more popular that when support for the old design was silently removed with the release of Windows 95, nobody seemed to notice, much less complain.
Windows 95 and Windows Vista revealed more cosmetic tweaks, with Windows 95 adding a grid of icons and Windows Vista adding live thumbnails to help you zip to the window you want more quickly. (By the way, here's a little-known feature: in Windows Vista, you can use the mouse to click on the thumbnail to switch directly to that window.)
Unfortunately, with all this excitement attached to Alt+Tab, another hotkey has been woefully neglected. Windows 2.0 introduced the Alt+Esc hotkey. Whereas Alt+Tab lets you pick an application, Alt+Esc lets you cycle through them.
When you press Alt+Esc, the active window is sent to the bottom of the window stack, allowing the window beneath it in the z-order to become the new active window. And if the next window is a minimized window, it stays minimized. While this may sound like an annoyance, it is actually a useful device, as it lets you skip past minimized applications without having to open them.
Say the window stack consists of windows A, B, C, and D, for example. Pressing Alt+Esc will push window A to the bottom (resulting in a stack order of B, C, D, A). Pressing it again will push window B to the bottom (resulting in C, D, A, B). Since Alt+Esc doesn't open minimized windows, if window B were minimized, it would remain so.
Adding the shift key to the Alt+Esc sequence does the reverse: the bottom window from the stack is brought to the top (but not opened). You can switch between two windows by putting one at the top of the window stack, putting another at the bottom, and then using Alt+Esc and Alt+Shift+Esc to switch between them.
While Alt+Tab got all the attention during the evolution of Windows, poor little Alt+Esc sat on the sidelines, sobbing quietly to itself for having been neglected all these years. But Alt+Esc's relative neglect has also been an advantage. While many developers write programs that attempt to enhance the Alt+Tab user interface, nobody messes with Alt+Esc.
Like a crystal radio during a power outage, Alt+Esc comes to the rescue when your Alt+Tab and other task-switching enhancements stop working. If your Alt+Tab enhancement has gone haywire and a bad shell extension has messed up your taskbar, don't despair. You can then dig into your bag of tricks and pull out Alt+Esc, the backup task switcher hotkey that's there when you need it, because it never occurs to anybody to interfere with it.
Raymond Chen's Web site, The Old New Thing, and identically titled book (Addison-Wesley, 2007) deal with Windows history, Win32 programming, and exploding coffee machines.