diff --git a/gdk/gdkwindow.c b/gdk/gdkwindow.c
index 320118472b..e8e3723b01 100644
--- a/gdk/gdkwindow.c
+++ b/gdk/gdkwindow.c
@@ -2833,6 +2833,7 @@ gdk_window_end_implicit_paint (GdkWindow *window)
       cr = gdk_cairo_create (private->impl);
       gdk_cairo_set_source_pixmap (cr, paint->pixmap,
                                    paint->x_offset, paint->y_offset);
+      cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
       gdk_cairo_region (cr, paint->region);
       cairo_fill (cr);
       cairo_destroy (cr);