XMonad.Layout.Spacing

import XMonad.Layout.Spacing(spacing)

opmLayout = avoidStruts (tabbed shrinkText opmTabConfig ||| tiled ||| Mirror tiled ||| Full)
    where
        -- default tiling algorithm partitions the screen into two panes
        tiled = spacing 2 $ Tall nmaster delta ratio

        -- The default number of windows in the master pane
        nmaster = 1

        -- Default proportion of screen occupied by master pane
        ratio = 1/2

        -- Percent of screen to increment by when resizing panes
        delta = 3/100