diff --git a/ChangeLog b/ChangeLog
index f1218268..95260ea8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2015-06-14  Lee Howard  <faxguy@howardsilvan.com>
 
+	* tools/tiffgt.c (raster_draw): contribution from Jay Berkenbilt 
+	on Bugzilla Bug #2401.  Appropriately call glFlush().
+
 	* tools/tiff2pdf.c: change ColorTransform from "0" to "1"
 	following Bugzilla Bug #2150.
 
diff --git a/tools/tiffgt.c b/tools/tiffgt.c
index 3907d302..8565111c 100644
--- a/tools/tiffgt.c
+++ b/tools/tiffgt.c
@@ -1,4 +1,4 @@
-/* $Id: tiffgt.c,v 1.11 2014-12-26 16:06:41 bfriesen Exp $ */
+/* $Id: tiffgt.c,v 1.12 2015-06-14 21:44:17 faxguy Exp $ */
 
 /*
  * Copyright (c) 1988-1997 Sam Leffler
@@ -287,6 +287,7 @@ static void
 raster_draw(void)
 {
   glDrawPixels(img.width, img.height, GL_RGBA, GL_UNSIGNED_BYTE, (const GLvoid *) raster);
+  glFlush();
 }
 
 static void