A UI is a UI. If your app has two sections that look the same it is still just one UI. As with all UIs, they will freeze if you perform some long-running operation on the main thread. You could get away with calling Application.DoEvents in very simple situations but you really should look at multi-threading. The BackgroundWorker class might be the first place to look. If you follow the CodeBank link in my signature you'll find my submission on that topic.