To use this module, add the following import to ~/.xmonad/xmonad.hs:

 import XMonad.Hooks.ManageDocks

The first component is a ManageHook which recognizes these windows and de-manages them, so that xmonad does not try to tile them. To enable it:

 manageHook = ... <+> manageDocks

The second component is a layout modifier that prevents windows from overlapping these dock windows. It is intended to replace xmonad's so-called "gap" support. First, you must add it to your list of layouts:

 layoutHook = avoidStruts (tall ||| mirror tall ||| ...)
                   where  tall = Tall 1 (3/100) (1/2)

AvoidStruts also supports toggling the dock gaps; add a keybinding similar to:

 ,((modMask x, xK_b     ), sendMessage ToggleStruts)

If you have multiple docks, you can toggle their gaps individually. For example, to toggle only the top gap:

 ,((modMask x .|. controlMask, xK_t), sendMessage $ ToggleStrut U)

Similarly, you can use D, L, and R to individually toggle gaps on the bottom, left, or right.

If you want certain docks to be avoided but others to be covered by default, you can manually specify the sides of the screen on which docks should be avoided, using avoidStrutsOn. For example:

 layoutHook = avoidStrutsOn [U,L] (tall ||| mirror tall ||| ...)

Important note: if you are switching from manual gaps (defaultGaps in your config) to avoidStruts (recommended, since manual gaps will probably be phased out soon), be sure to switch off all your gaps (with mod-b) before reloading your config with avoidStruts! Toggling struts with a ToggleStruts message will not work unless your gaps are set to zero.

For detailed instructions on editing your key bindings, see XMonad.Doc.Extending.