@@ -, +, @@ 
---
 src/xcb_io.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)
--- a/src/xcb_io.c	
+++ a/src/xcb_io.c	
@@ -704,14 +704,18 @@ Status _XReply(Display *dpy, xReply *rep, int extra, Bool discard)
 		if(dpy->xcb->event_owner == XlibOwnsEventQueue)
 		{
 			xcb_generic_reply_t *event;
-
-			/* Assume event queue is empty if another thread is blocking
-			 * waiting for event. */
-			if(!dpy->xcb->event_waiter)
-			{
-				while((event = poll_for_response(dpy)))
-					handle_response(dpy, event, True);
-                        }
+			/* If some thread is already waiting for events,
+			 * it will get the first one. That thread must
+			 * process that event before we can continue. */
+			/* FIXME: That event might be after this reply,
+			 * and might never even come--or there might be
+			 * multiple threads trying to get events. */
+			while(dpy->xcb->event_waiter)
+			{ /* need braces around ConditionWait */
+				ConditionWait(dpy, dpy->xcb->event_notify);
+			}
+			while((event = poll_for_event(dpy, True)))
+				handle_response(dpy, event, True);
 		}
 
 		req->reply_waiter = 0;
--