New Post: Progress of Rendering

I am using C# Visual Studio 2013. To get this to mostly work I had to be more explicit with the names:

participant.ProgressChanged += new EventHandler<Splicer.Renderer.ProgressChangedEventArgs>(participant_ProgressChanged);

And the callback function:
private void participant_ProgressChanged(object sender, Splicer.Renderer.ProgressChangedEventArgs e)

    {
        int iProgress =  (int)(e.Progress * 100);
        toolStripProgressBar1.Value = iProgress;
    }

My problem is that the Renderer seems to be holding the CPU time and not yielding any time as to allow the progressbar to refresh. For now, I just put a progressbar on the right side of the toolstrip menu. It does not show progress, even though can put breakpoints in the callback function and it is being called and e.Progress is a valid double between 0 and 1 (progressing toward 1.

Any idea how to get the Renderer to yield so that my progressbar refreshes?