From 1a3cb2be4de7e6945372aa5292dbe13b691c9f86 Mon Sep 17 00:00:00 2001
From: narzoul <narzoul@users.noreply.github.com>
Date: Wed, 6 Apr 2016 22:35:54 +0200
Subject: [PATCH] Added invalidation of non-client area on WM_ACTIVATE

---
 DDrawCompat/CompatGdiWinProc.cpp | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/DDrawCompat/CompatGdiWinProc.cpp b/DDrawCompat/CompatGdiWinProc.cpp
index ae6e9c4..cd5064b 100644
--- a/DDrawCompat/CompatGdiWinProc.cpp
+++ b/DDrawCompat/CompatGdiWinProc.cpp
@@ -18,6 +18,7 @@ namespace
 	std::unordered_map<HWND, RECT> g_prevWindowRect;
 
 	void disableDwmAttributes(HWND hwnd);
+	void onActivate(HWND hwnd);
 	void onMenuSelect();
 	void onWindowPosChanged(HWND hwnd);
 	void removeDropShadow(HWND hwnd);
@@ -43,6 +44,10 @@ namespace
 			{
 				onWindowPosChanged(ret->hwnd);
 			}
+			else if (WM_ACTIVATE == ret->message)
+			{
+				onActivate(ret->hwnd);
+			}
 			else if (WM_COMMAND == ret->message)
 			{
 				auto notifCode = HIWORD(ret->wParam);
@@ -95,7 +100,7 @@ namespace
 			{
 				if (OBJID_TITLEBAR == idObject)
 				{
-					CompatGdi::TitleBar(hwnd, compatDc).drawAll();
+					CompatGdi::TitleBar(hwnd, compatDc).drawButtons();
 				}
 				else if (OBJID_HSCROLL == idObject)
 				{
@@ -113,6 +118,24 @@ namespace
 		}
 	}
 
+	void onActivate(HWND hwnd)
+	{
+		RECT windowRect = {};
+		GetWindowRect(hwnd, &windowRect);
+		RECT clientRect = {};
+		GetClientRect(hwnd, &clientRect);
+		POINT clientOrigin = {};
+		ClientToScreen(hwnd, &clientOrigin);
+		OffsetRect(&windowRect, -clientOrigin.x, -clientOrigin.y);
+
+		HRGN ncRgn = CreateRectRgnIndirect(&windowRect);
+		HRGN clientRgn = CreateRectRgnIndirect(&clientRect);
+		CombineRgn(ncRgn, ncRgn, clientRgn, RGN_DIFF);
+		RedrawWindow(hwnd, nullptr, ncRgn, RDW_FRAME | RDW_INVALIDATE);
+		DeleteObject(clientRgn);
+		DeleteObject(ncRgn);
+	}
+
 	void onMenuSelect()
 	{
 		HWND menuWindow = FindWindow(reinterpret_cast<LPCSTR>(0x8000), nullptr);