Index: pgm/utils/benchmark.py
===================================================================
--- pgm/utils/benchmark.py      (revision 1082)
+++ pgm/utils/benchmark.py      (working copy)
@@ -174,6 +174,8 @@
         if self._fps:
             os.environ['PGM_GL_FPS'] = self._fps
         self.gl.set_canvas(None)
+        self.gl.visible = False
+        self.gl.hide()
         del self.gl
         if self.callback:
             self.callback(self.result)