Fix Bitinvader waveform cutoff behavior

src/gui/widgets/Graph.cpp

@@ -692,7 +692,15 @@ void graphModel::shiftPhase( int _deg )
 	emit samplesChanged( 0, length()-1 );
 }
 
-
+// Clear any part of the graph that isn't displayed
+void graphModel::clearInvisible()
+{
+	const int graph_length = length();
+	const int full_graph_length = m_samples.size();
+	for( int i = graph_length; i < full_graph_length; i++ )
+		m_samples[i] = 0;
+	emit samplesChanged( graph_length, full_graph_length - 1 );
+}
 
 void graphModel::drawSampleAt( int x, float val )
 {