Prevent the "X Error (bad Atom)" situation that causes an
"X Error" panic.
The issue isn't fixed. This fails to implement the intended
functionality of having the X server remember the persistent
inventory window's location across games (until the next time
that the X server restarts). Worse, on OSX the window creeps
each time it is updated (visually it seems to be moving down by
the height of the window's title bar).
That's not as bad as having it move to the pointer's location as
it did in 3.6.1, but prior to the commit which introduced this
code that had been fixed and it stayed put during the current
game, so more work is definitely needed.
67d94d2930