diff --git a/freeglut/freeglut/src/freeglut_main.c b/freeglut/freeglut/src/freeglut_main.c
index 34e284b..6935ff1 100644
--- a/freeglut/freeglut/src/freeglut_main.c
+++ b/freeglut/freeglut/src/freeglut_main.c
@@ -1214,11 +1214,16 @@ LRESULT CALLBACK fgWindowProc( HWND hWnd, UINT uMsg, WPARAM wParam,
 
     case WM_SIZE:
         /*
-         * We got resized... But check if the window has been already added...
+         * If the window is visible, then it is the user manually resizing it.
+         * If it is not, then it is the system sending us a dummy resize with
+         * zero dimensions on a "glutIconifyWindow" call.
          */
-        window->State.NeedToResize = GL_TRUE;
-        window->State.Width  = LOWORD(lParam);
-        window->State.Height = HIWORD(lParam);
+        if( window->State.Visible )
+        {
+            window->State.NeedToResize = GL_TRUE;
+            window->State.Width  = LOWORD(lParam);
+            window->State.Height = HIWORD(lParam);
+        }
         break;
 #if 0
     case WM_SETFOCUS: 
diff --git a/freeglut/freeglut/src/freeglut_window.c b/freeglut/freeglut/src/freeglut_window.c
index c92fbcb..12e6b52 100644
--- a/freeglut/freeglut/src/freeglut_window.c
+++ b/freeglut/freeglut/src/freeglut_window.c
@@ -719,6 +719,8 @@ void FGAPIENTRY glutIconifyWindow( void )
     freeglut_assert_ready;
     freeglut_assert_window;
 
+    fgStructure.Window->State.Visible   = GL_FALSE;
+
 #if TARGET_HOST_UNIX_X11
 
     XIconifyWindow( fgDisplay.Display, fgStructure.Window->Window.Handle,