So: with my focus on the Emacs, I [C-c C-e d] (control-c, control-e,
d) and watch the export process go. Evince updates with the view of
the new document.
... And my focus is now oddly inconsistent. The Emacs window still
has the red border by which xmonad attempts to communicate focus, and
if I do things like 'onNextNeighbour W.view' it becomes clear that
xmonad thinks my focus is there. But my keystrokes are going to
evince.
evince is probably raising / focusing itself. It should ask the WM to do so instead of doing so itself, but doesn't; and there have been other reports that xmonad doesn't notice when programs do that. I suspect an addition to the handleEventHook is needed that watches for FocusIn events and updates the internal state if necessary.
...except I just noticed that Graphics.X11.Xlib.Extras.Event doesn't *have* FocusIn. Errrr???