Fix triggering of stop animation when playing no samples after stopping song playing samples

include/SampleTrack.h

@@ -167,6 +167,11 @@ public:
 		return m_wasPlaying;
 	}
 
+	void setWasPlaying(bool wasPlaying)
+	{
+		m_wasPlaying = wasPlaying;
+	}
+
 signals:
 	void playing();
 	void notPlaying();

src/tracks/SampleTrack.cpp

@@ -984,9 +984,11 @@ void SampleTrackView::dropEvent(QDropEvent *de)
 
 void SampleTrackView::stopPlaying()
 {
-	if (dynamic_cast<SampleTrack*>(getTrack())->wasPlaying())
+	SampleTrack * smpltrck = dynamic_cast<SampleTrack*>(getTrack());
+	if (smpltrck->wasPlaying())
 	{
 		m_activityIndicator->notPlaying();
+		smpltrck->setWasPlaying(false);
 	}
 }