If you like to use alt+tab hotkey to switch between opened documents and applications, you have to know what that dialog has a lots of parameters. By default it looks like this


And can look like this:


As usual, its not possible to change settings using Windows Control Panel.

Alt+Tab Tuner is little portable application which can help to change all hidden settings of Alt+Tab Dialog

You can adjust the margins on the top, bottom, or side of the global preview window; change the number of columns and rows that those previews appear in; and change the amount of spacing between each preview thumbnail. Users can also tweak the program icon location and size; the preview thumbnail size; the milliseconds the global preview window takes to desktop fade out; and the opacity of the previews' transparency.

Download Alt+Tab Tuner