From 9fab115a6774d0168e192fe33d45242bc9a4c459 Mon Sep 17 00:00:00 2001
From: mchinen <mchinen@47890b92-0858-11df-a26f-8b716316a5bc>
Date: Sun, 19 May 2013 05:56:42 +0000
Subject: [PATCH] Effect.cpp: fix crash on preview while creating chains. Patch
 by Steve Daulton.

---
 src/effects/Effect.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/effects/Effect.cpp b/src/effects/Effect.cpp
index 6cea8cdc2..3ac7486a4 100644
--- a/src/effects/Effect.cpp
+++ b/src/effects/Effect.cpp
@@ -415,6 +415,9 @@ wxString Effect::GetPreviewName()
 
 void Effect::Preview(bool dryOnly)
 {
+   if (mNumTracks==0) // nothing to preview
+      return;
+
    wxWindow* FocusDialog = wxWindow::FindFocus();
    if (gAudioIO->IsBusy())
       return;