xna - Spritebatch not working in winforms

I'm using the Winforms sample on the app hub and everything is working fine except my spritebatch won't draw anything unless I call Invalidate in the Draw method. I have this in my initialize method:

Application.Idle += delegate { Invalidate(); }; 

I used a breakpoint and it is indeed invalidating my program and it is calling my draw method. I get no errors with the spritebatch and all the textures are loaded I just don't see anything on the screen. Here's the code I have:

    protected override void Draw()
    {
        GraphicsDevice.Clear(Color.CornflowerBlue);
        spriteBatch.Begin();
        tileSheet.Draw(spriteBatch);
        foreach (Image img in selector)
            img.Draw(spriteBatch);
        spriteBatch.End();
    }

But when I do this:

    protected override void Draw()
    {
        GraphicsDevice.Clear(Color.CornflowerBlue);
        spriteBatch.Begin();
        tileSheet.Draw(spriteBatch);
        foreach (Image img in selector)
            img.Draw(spriteBatch);
        spriteBatch.End();

        Invalidate();
    }

then all of a sudden the drawing starts to work! but the problem is that it freezes everything else and only that control gets updated. What can I do to fix this? It's really frustrating.