From a9983101ab50d506c2fce554650bbc1e915d7e8d Mon Sep 17 00:00:00 2001
From: Jinhao <cnjinhao@hotmail.com>
Date: Tue, 13 Oct 2015 23:11:57 +0800
Subject: [PATCH] avoid double-copying a window while its parent is refreshing

---
 source/gui/detail/window_manager.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/source/gui/detail/window_manager.cpp b/source/gui/detail/window_manager.cpp
index 3cb72140..ea26fd02 100644
--- a/source/gui/detail/window_manager.cpp
+++ b/source/gui/detail/window_manager.cpp
@@ -676,6 +676,14 @@ namespace detail
 			std::lock_guard<decltype(mutex_)> lock(mutex_);
 			if (impl_->wd_register.available(wd) && !wd->is_draw_through())
 			{
+				auto parent = wd->parent;
+				while (parent)
+				{
+					if (parent->flags.refreshing)
+						return;
+					parent = parent->parent;
+				}
+
 				//Copy the root buffer that wd specified into DeviceContext
 #if defined(NANA_LINUX)
 				wd->drawer.map(reinterpret_cast<window>(wd), forced, update_area);