diff --git a/collects/mred/private/wx/cocoa/image.rkt b/collects/mred/private/wx/cocoa/image.rkt
index ac05763af8..e6b86f4bb0 100644
--- a/collects/mred/private/wx/cocoa/image.rkt
+++ b/collects/mred/private/wx/cocoa/image.rkt
@@ -134,4 +134,5 @@
              operation: #:type _int NSCompositeCopy fraction: #:type _CGFloat 1.0))
     (tellv NSGraphicsContext restoreGraphicsState)
     (CGContextRestoreGState cg)
+    (cairo_surface_mark_dirty surface)
     bm))