Added a comment explaining the MapRequestEvents change from b9394a2.

Author: whitelynx

xpybutil/event.py

@@ -131,6 +131,8 @@ def main():
                 if isinstance(e, xproto.MappingNotifyEvent):
                     w = None
                 elif isinstance(e, xproto.MapRequestEvent):
+                    # Force all MapRequestEvents to go to the root window so
+                    # a window manager using xpybutil can get them.
                     w = root
                 elif hasattr(e, 'window'):
                     w = e.window