diff --git a/src/Main/fg_os.cxx b/src/Main/fg_os.cxx
index 5d14659aa..6a55e23d5 100644
--- a/src/Main/fg_os.cxx
+++ b/src/Main/fg_os.cxx
@@ -217,4 +217,8 @@ void fgOSOpenWindow(int w, int h, int bpp, bool alpha,
     glutDisplayFunc(GLUTdraw);
     glutReshapeFunc(GLUTreshape);
 
+    glutShowWindow();
+    glClear(GL_COLOR_BUFFER_BIT);
+    glutSwapBuffers();
+    glutPostRedisplay();
 }