There were two bugs:
1. The layout modifier assumed the rect's x was zero.
2. The layout modifier assumed that the stackset's focus actually had focus.
This patch will allow the user to split the currently focused screen instead of all screens together. This is usefull for multiscreen users who have functioning xinerama, but wish to split one of the screens.
The problem was that certain layouts keep their "world" state in their value,
which was thrown away and forgotten after ReleaseResources during toggle.
In particular, decorated layouts store some X11 handles in them and
allocate/deallocate it as appropriate. If any modification to their state is
ignored, they may try to deallocate already deallocated memory, which results
in a crash somewhere inside Xlib.
This patch makes Transformers reversible so that nothing is ever ignored. As a
side effect, layout transformers now do receive messages and messages for the
base layout do not need the undo/reapply cycle -- we just pass messages to the
current transformed layout and unapply the transformer when needed.
(This, however, doesn't mean that the base layout is not asked to release
resources on a transformer change -- we still need the transformer to release
its resources and there's no way to do this without asking the base layout as
well.)
The description for mirrored MouseResizableTile is now "Mirror
MouseResizableTile", to follow the standard of other layouts that can be
mirrored using the Mirror modifier.
Fix bug where a column list of insufficient length could be used to find the column of the window. Also fix formating to conform better with standards.
New layout inspired the realization that I was switching between Mirror Tall and Mirror ThreeCol depending on how many windows there were on the workspace. This layout will make those changes automatically.
Despite myLayouts currently being more popular in examples, make
them all myLayout as in man/xmonad.hs to avoid mixing them in the
same module as was done a few places, leading to confusion for some users.
