[Xmonad] darcs patch: use a global IORef to keep list of urgent windows

[Devin Mullins]

On Sat, Oct 27, 2007 at 02:52:28AM -0400, Devin Mullins wrote:
>  - If it's bug-free (no space-leaks, safe-ish unsafePerformIO, etc.)

Well, after looking at some of the relevant comments in
GHC/{IOBase,STRef,ST}.lhs, I feel more confident that both are true.
1. The NOINLINE should eliminate duplicate newIORefs and order of ops is
   safe here.
2. IORef (at least in GHC) use STRef, which uses ST, which is strict in
   its state.

However, I'm having some other odd problems (repeatable!):
 - If I mod-q xmonad while xchat is the current window, xchat no longer
   sends urgent events. Opening prefs and hitting ok (no changes) fixes
   it.
 - If I mod-q xmonad while I've got a child dzen process open (via
   XMC.Dzen.dzenUrgencyHook), the new xmonad no longer responds to
   keyboard events. It responds to mouse events (the border moves with
   focus). This is not the case for dzens spawned via:
     spawn "(date; sleep 2) | dzen2"

   In fact, the behavior is a little more nuanced. After I mod-q, while
   the dzen is still open, I can hit mod-j, and I see the focus
   temporarily move, and then snap back when I keyup. After the dzen
   goes, 'j' gets sent to the client window.

Help!

Devin