From a668db8b64323a31bddb96adc7641a379e294b68 Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Fri, 11 Oct 2019 15:34:49 +0200
Subject: [PATCH] Do nothing in wxListCtrl::SetDoubleBuffered() in wxMSW

Setting WS_EX_COMPOSITED, as the base class version does, just results
in visual artefacts and is useless, as we turn on LVS_EX_DOUBLEBUFFER
already, if it's supported, anyhow.

So don't break the display if people call SetDoubleBuffered() in the
mistaken belief that it does something useful in this case.
---
 include/wx/msw/listctrl.h |  5 +++++
 src/msw/listctrl.cpp      | 11 +++++++++++
 2 files changed, 16 insertions(+)

diff --git a/include/wx/msw/listctrl.h b/include/wx/msw/listctrl.h
index 59794184af..68c5c65f23 100644
--- a/include/wx/msw/listctrl.h
+++ b/include/wx/msw/listctrl.h
@@ -360,6 +360,11 @@ public:
     // Necessary for drawing hrules and vrules, if specified
     void OnPaint(wxPaintEvent& event);
 
+    // Override SetDoubleBuffered() to do nothing, its implementation in the
+    // base class is incompatible with the double buffering done by this native
+    // control.
+    virtual bool IsDoubleBuffered() const;
+    virtual void SetDoubleBuffered(bool on);
 
     virtual bool ShouldInheritColours() const wxOVERRIDE { return false; }
 
diff --git a/src/msw/listctrl.cpp b/src/msw/listctrl.cpp
index c3de6a8bfa..5f6f922854 100644
--- a/src/msw/listctrl.cpp
+++ b/src/msw/listctrl.cpp
@@ -466,6 +466,17 @@ void wxListCtrl::OnDPIChanged(wxDPIChangedEvent &event)
     }
 }
 
+bool wxListCtrl::IsDoubleBuffered() const
+{
+    // LVS_EX_DOUBLEBUFFER is turned on for comctl32 v6+.
+    return wxApp::GetComCtl32Version() >= 600;
+}
+
+void wxListCtrl::SetDoubleBuffered(bool WXUNUSED(on))
+{
+    // Nothing to do, it's always enabled if supported.
+}
+
 #if WXWIN_COMPATIBILITY_3_0
 // Deprecated
 void wxListCtrl::UpdateStyle()