Fixed '_functionTimer' not be disposed after quit if it's running. (#2007)

UICatalog/Scenarios/ProgressBarStyles.cs

@@ -135,11 +135,15 @@ namespace UICatalog.Scenarios {
 
 			void Top_Unloaded ()
 			{
+				if (_fractionTimer != null) {
+					_fractionTimer.Dispose ();
+					_fractionTimer = null;
+				}
 				if (_pulseTimer != null) {
 					_pulseTimer.Dispose ();
 					_pulseTimer = null;
-					Top.Unloaded -= Top_Unloaded;
 				}
+				Top.Unloaded -= Top_Unloaded;
 			}
 		}
 	}