From 43291687a5a10e873e8be9971a8f7272c7b4927b Mon Sep 17 00:00:00 2001
From: Darrell Walisser <darrell.walisser@gmail.com>
Date: Sat, 25 Feb 2017 16:16:42 -0500
Subject: [PATCH] Bug 1401 - Wait for window visibility before starting timer

---
 src/TrackPanel.cpp | 21 ++++++++++++++++++++-
 src/TrackPanel.h   |  1 +
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/TrackPanel.cpp b/src/TrackPanel.cpp
index 623a98754..5a4b1da71 100644
--- a/src/TrackPanel.cpp
+++ b/src/TrackPanel.cpp
@@ -516,7 +516,8 @@ TrackPanel::TrackPanel(wxWindow * parent, wxWindowID id,
 
    mTimeCount = 0;
    mTimer.parent = this;
-   mTimer.Start(kTimerInterval, FALSE);
+   // Timer is started after the window is visible
+   GetProject()->Bind(wxEVT_IDLE, &TrackPanel::OnIdle, this);
 
    //Initialize a member variable pointing to the current
    //drawing track.
@@ -904,6 +905,24 @@ AudacityProject * TrackPanel::GetProject() const
    return (AudacityProject*)pWind;
 }
 
+void TrackPanel::OnIdle(wxIdleEvent& event)
+{
+   // The window must be ready when the timer fires (#1401)
+   if (IsShownOnScreen())
+   {
+      mTimer.Start(kTimerInterval, FALSE);
+
+      // Timer is started, we don't need the event anymore
+      GetProject()->Unbind(wxEVT_IDLE, &TrackPanel::OnIdle, this);
+   }
+   else
+   {
+      // Get another idle event, wx only guarantees we get one
+      // event after "some other normal events occur"
+      event.RequestMore();
+   }
+}
+
 /// AS: This gets called on our wx timer events.
 void TrackPanel::OnTimer(wxTimerEvent& )
 {
diff --git a/src/TrackPanel.h b/src/TrackPanel.h
index 6c09d0631..b8d719217 100644
--- a/src/TrackPanel.h
+++ b/src/TrackPanel.h
@@ -171,6 +171,7 @@ class AUDACITY_DLL_API TrackPanel final : public OverlayPanel {
 
    virtual double GetMostRecentXPos();
 
+   virtual void OnIdle(wxIdleEvent & event);
    virtual void OnTimer(wxTimerEvent& event);
 
    virtual int GetLeftOffset() const { return GetLabelWidth() + 1;}