After using GridVariants.TallGrid for a while, I got fed up with the fact that the meaning of columns and rows get exchanged when TallGrid is rotated using Mirror (as well as with other small nuisances). The attached patch contains a new layout, GridVariants.SplitGrid, which allows the orientation of the split between the master and the slave grid to be specified as a parameter, thus doing away with the need to use Mirror or Reflect with this layout. What SplitGrid and TallGrid do should be achievable using the standard Grid layout plus a layout combinator. However, the automatic assignment of clients to the master/slave grids would require more plumbing in xmonad.hs, which is why I opted for writing this as a separate layout. Cheers, Norbert