$OpenBSD$

index 294c74f..4cdac97 100644
--- dom/events/Event.cpp.orig	Fri Feb 20 15:40:37 2015
+++ dom/events/Event.cpp	Fri Feb 20 15:40:37 2015
@@ -829,6 +829,19 @@ Event::GetScreenCoords(nsPresContext* aPresContext,
                        WidgetEvent* aEvent,
                        LayoutDeviceIntPoint aPoint)
 {
+  if (!nsContentUtils::IsCallerChrome()) {
+    // For non-chrome callers, return client coordinates instead.
+    // For some events, the result will be zero; specifically, for dragend
+    // events (there is no widget associated with dragend events, which
+    // causes GetClientX() to return zero).  Since dragend is for the drag
+    // originator and not for the receiver, it is probably not widely used
+    // (receivers get a drop event).  Therefore, returning 0 should not break
+    // many web pages.  Also, a few years ago Firefox returned 0.
+    // See:  https://bugzilla.mozilla.org/show_bug.cgi?id=466379
+    CSSIntPoint clientCoords = GetClientCoords(aPresContext, aEvent, aPoint, CSSIntPoint(0, 0));
+    return nsIntPoint(clientCoords.x, clientCoords.y);
+  }
+
   if (EventStateManager::sIsPointerLocked) {
     return EventStateManager::sLastScreenPoint;
   }