[xmonad] Combo fix ReleaseResources when no windows are available

[Anders Engström]

Hello. I dug around some in X.L.Combo and noticed some strangeness,
integrate cannot return empty lists (but integrate' can). The code
expect it to return an empty list if there are no windows to display.
Actually the function will never be called since emptyLayout is used
instead of doLayout when there are no windows to display. All this
results in that ReleaseResources is not sent to the underlying
layouts. I fixed it by introducing emptyLayout but it is also possible
to do it by using runLayout instead, but this seem cleaner.
/Anders Engström
-------------- next part --------------
A non-text attachment was scrubbed...
Name: combo-releaseresources.dpatch
Type: application/octet-stream
Size: 27191 bytes
Desc: not available
Url : http://www.haskell.org/pipermail/xmonad/attachments/20090222/71b1791a/combo-releaseresources-0001.obj