[Xmonad] mod-{w,e,r} don't work when OpenOffice.org has focus

[Kai Grossjohann]

I have two heads, the left one shows workspace 1 which is in full layout
and contains OpenOffice, Firefox and Adobe Reader.  The right head shows
different workspaces as time goes by, usually in tiled layout.

Now it turns out that OpenOffice somehow grabs focus so that mod-e does
not work to switch to the second head.  I can still do mod-j to switch
to a different client on the left head, and then mod-e works.  But when
OpenOffice has focus and after I click into it, then mod-e will not work
to set the focus to the right hand head.

Has anyone else observed the same?  Is there a fix?  What can I do to
help debug it?  (I don't grok Haskell, though I'm trying.)

Kai