Clarified when to use ESC 9

Example/demo.cs

@@ -137,7 +137,7 @@ static class Demo {
 			new Button (3, 19, "Ok"),
 			new Button (10, 19, "Cancel"),
 			progress,
-			new Label (3, 22, "Press ESC and 9 to activate the menubar")
+			new Label (3, 22, "Press F9 (on Unix, ESC+9 is an alias) to activate the menubar")
 		);
 
 	}

StandaloneExample/Program.cs

@@ -136,7 +136,7 @@ class Demo {
 			new Button ("Ok") { X = 3, Y = 19 },
 			new Button ("Cancel") { X = 10, Y = 19 },
 			progress,
-			new Label ("Press ESC and 9 to activate the menubar") { X = 3, Y = 22 }
+			new Label ("Press F9 (on Unix ESC+9 is an alias) to activate the menubar") { X = 3, Y = 22 }
 		);
 
 	}