I found a big problem that GC cannot collect the graphic object whick not use any more. I think the follow methods cannot release object automatic.
WaveformGraph.Plots.Clear();
WaveformGraph.Annotations.Clear();
WaveformGraph.Cursors.Clear();
WaveformGraph.XAxes.Clear();
WaveformGraph.YAxes.Clear();
Is there has a way to release the graohic object?