From fd9ac6bf099e8501a53faa6d5b34c80a0afc9c1d Mon Sep 17 00:00:00 2001
From: "james.k.crook" <james.k.crook@47890b92-0858-11df-a26f-8b716316a5bc>
Date: Sat, 12 Feb 2011 18:33:49 +0000
Subject: [PATCH] Fix: slowdown with many labels caused by LyricsWindow.  (Bug
 144)

---
 src/Menus.cpp   | 1 +
 src/Project.cpp | 7 +++++++
 2 files changed, 8 insertions(+)

diff --git a/src/Menus.cpp b/src/Menus.cpp
index 55b5d3a46..d67e26ad8 100644
--- a/src/Menus.cpp
+++ b/src/Menus.cpp
@@ -4493,6 +4493,7 @@ void AudacityProject::OnKaraoke()
    if (!mLyricsWindow)
       mLyricsWindow = new LyricsWindow(this);
    mLyricsWindow->Show();
+   UpdateLyrics();
    mLyricsWindow->Raise();
 }
 
diff --git a/src/Project.cpp b/src/Project.cpp
index 892ab6928..76a0fb53e 100644
--- a/src/Project.cpp
+++ b/src/Project.cpp
@@ -3653,6 +3653,13 @@ void AudacityProject::UpdateLyrics()
       mLyricsWindow->Show(false); // Don't show it. Need to update content regardless.
    }
 
+   // The code that updates the lyrics is rather expensive when there
+   // are a lot of labels.
+   // So - bail out early if the lyrics window is not visible.
+   // We will later force an update when the lyrics window is made visible.
+   if( !mLyricsWindow->IsVisible() )
+      return;
+
    Lyrics* pLyricsPanel = mLyricsWindow->GetLyricsPanel();
    pLyricsPanel->Clear();
    for (int i = 0; i < pLabelTrack->GetNumLabels(); i++)