A decoration that allows to switch the position of windows by dragging them onto each other.

You can use this module with the following in your ~/.xmonad/xmonad.hs:

 import XMonad.Layout.WindowSwitcherDecoration
 import XMonad.Layout.DraggingVisualizer

Then edit your layoutHook by adding the WindowSwitcherDecoration to your layout:

 myL = windowSwitcherDecoration shrinkText defaultTheme (draggingVisualizer $ layoutHook defaultConfig)
 main = xmonad defaultConfig { layoutHook = myL }

There is also a version of the decoration that contains buttons like XMonad.Layout.ButtonDecoration. To use that version, you will need to import XMonad.Layout.DecorationAddons as well and modify your layoutHook in the following way:

 import XMonad.Layout.DecorationAddons

 myL = windowSwitcherDecorationWithButtons shrinkText defaultThemeWithButtons (draggingVisualizer $ layoutHook defaultConfig)
 main = xmonad defaultConfig { layoutHook = myL }