Fix possible crash when updating progress bar;

Author: KonH

UnityProject/Assets/RefAnalyzer/Editor/UI/ExporterWindow.cs

@@ -29,11 +29,10 @@ void OnGUI() {
 				OnRefreshData();
 			}
 			GUILayout.EndArea();
-			UpdateProgress();
 		}
 
 		void OnInspectorUpdate() {
-			Repaint();
+			UpdateProgress();
 		}
 
 		void OnRefreshData() {