diff --git a/DDrawCompat/Config/Config.cpp b/DDrawCompat/Config/Config.cpp
index 532c4ff..3126db3 100644
--- a/DDrawCompat/Config/Config.cpp
+++ b/DDrawCompat/Config/Config.cpp
@@ -3,6 +3,7 @@
 namespace Config
 {
 	Settings::AlternatePixelCenter alternatePixelCenter;
+	Settings::AltTabFix altTabFix;
 	Settings::Antialiasing antialiasing;
 	Settings::ConfigHotKey configHotKey;
 	Settings::CpuAffinity cpuAffinity;
diff --git a/DDrawCompat/Config/Config.h b/DDrawCompat/Config/Config.h
index a56b4c6..68cb4a2 100644
--- a/DDrawCompat/Config/Config.h
+++ b/DDrawCompat/Config/Config.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <Config/Settings/AlternatePixelCenter.h>
+#include <Config/Settings/AltTabFix.h>
 #include <Config/Settings/Antialiasing.h>
 #include <Config/Settings/ConfigHotKey.h>
 #include <Config/Settings/CpuAffinity.h>
@@ -23,6 +24,7 @@
 namespace Config
 {
 	extern Settings::AlternatePixelCenter alternatePixelCenter;
+	extern Settings::AltTabFix altTabFix;
 	extern Settings::Antialiasing antialiasing;
 	extern Settings::ConfigHotKey configHotKey;
 	extern Settings::CpuAffinity cpuAffinity;
diff --git a/DDrawCompat/Config/Settings/AltTabFix.h b/DDrawCompat/Config/Settings/AltTabFix.h
new file mode 100644
index 0000000..af444ef
--- /dev/null
+++ b/DDrawCompat/Config/Settings/AltTabFix.h
@@ -0,0 +1,24 @@
+#pragma once
+
+#include <Config/EnumSetting.h>
+
+namespace Config
+{
+	namespace Settings
+	{
+		class AltTabFix : public MappedSetting<UINT>
+		{
+		public:
+			static const UINT OFF = 0;
+			static const UINT KEEPVIDMEM = 1;
+
+			AltTabFix()
+				: MappedSetting("AltTabFix", "off", {
+					{"off", OFF},
+					{"keepvidmem", KEEPVIDMEM}
+					})
+			{
+			}
+		};
+	}
+}
diff --git a/DDrawCompat/DDraw/DirectDraw.cpp b/DDrawCompat/DDraw/DirectDraw.cpp
index 1d44506..038942d 100644
--- a/DDrawCompat/DDraw/DirectDraw.cpp
+++ b/DDrawCompat/DDraw/DirectDraw.cpp
@@ -1,19 +1,26 @@
 #include <map>
+#include <set>
 #include <sstream>
 
 #include <Common/Comparison.h>
 #include <Common/CompatPtr.h>
 #include <Common/CompatVtable.h>
+#include <Config/Config.h>
 #include <D3dDdi/Adapter.h>
+#include <D3dDdi/Device.h>
 #include <D3dDdi/KernelModeThunks.h>
+#include <D3dDdi/Resource.h>
 #include <DDraw/DirectDraw.h>
+#include <DDraw/DirectDrawSurface.h>
 #include <DDraw/RealPrimarySurface.h>
 #include <DDraw/ScopedThreadLock.h>
 #include <DDraw/Surfaces/PrimarySurface.h>
+#include <DDraw/Surfaces/TagSurface.h>
 #include <DDraw/Visitors/DirectDrawVtblVisitor.h>
 
 namespace
 {
+	const DWORD SURFACE_LOST_FLAG = 0x10000000;
 
 	template <typename TDirectDraw, typename TSurfaceDesc, typename TSurface>
 	HRESULT STDMETHODCALLTYPE CreateSurface(
@@ -70,6 +77,17 @@ namespace
 		return getOrigVtable(This).RestoreAllSurfaces(This);
 	}
 
+	template <typename TDirectDraw>
+	HRESULT STDMETHODCALLTYPE SetCooperativeLevel(TDirectDraw* This, HWND hWnd, DWORD dwFlags)
+	{
+		HRESULT result = getOrigVtable(This).SetCooperativeLevel(This, hWnd, dwFlags);
+		if (SUCCEEDED(result))
+		{
+			DDraw::TagSurface::create(*CompatPtr<IDirectDraw>::from(This));
+		}
+		return result;
+	}
+
 	template <typename TDirectDraw>
 	HRESULT STDMETHODCALLTYPE WaitForVerticalBlank(TDirectDraw* This, DWORD dwFlags, HANDLE hEvent)
 	{
@@ -78,12 +96,44 @@ namespace
 		return getOrigVtable(This).WaitForVerticalBlank(This, dwFlags, hEvent);
 	}
 
+	HRESULT WINAPI restoreSurfaceLostFlag(
+		LPDIRECTDRAWSURFACE7 lpDDSurface, LPDDSURFACEDESC2 /*lpDDSurfaceDesc*/, LPVOID lpContext)
+	{
+		auto& surfacesToRestore = *static_cast<std::set<void*>*>(lpContext);
+		auto it = surfacesToRestore.find(DDraw::DirectDrawSurface::getSurfaceObject(*lpDDSurface));
+		if (it != surfacesToRestore.end())
+		{
+			DWORD& flags = DDraw::DirectDrawSurface::getFlags(*lpDDSurface);
+			flags &= ~SURFACE_LOST_FLAG;
+			surfacesToRestore.erase(it);
+		}
+		return DDENUMRET_OK;
+	}
+
+	HRESULT WINAPI setSurfaceLostFlag(
+		LPDIRECTDRAWSURFACE7 lpDDSurface, LPDDSURFACEDESC2 /*lpDDSurfaceDesc*/, LPVOID lpContext)
+	{
+		auto& surfacesToRestore = *static_cast<std::set<void*>*>(lpContext);
+		DWORD& flags = DDraw::DirectDrawSurface::getFlags(*lpDDSurface);
+		if (!(flags & SURFACE_LOST_FLAG))
+		{
+			auto resource = D3dDdi::Device::findResource(DDraw::DirectDrawSurface::getDriverResourceHandle(*lpDDSurface));
+			if (resource && !resource->getOrigDesc().Flags.MatchGdiPrimary)
+			{
+				flags |= SURFACE_LOST_FLAG;
+				surfacesToRestore.insert(DDraw::DirectDrawSurface::getSurfaceObject(*lpDDSurface));
+			}
+		}
+		return DDENUMRET_OK;
+	}
+
 	template <typename Vtable>
 	constexpr void setCompatVtable(Vtable& vtable)
 	{
 		vtable.CreateSurface = &CreateSurface;
 		vtable.FlipToGDISurface = &FlipToGDISurface;
 		vtable.GetGDISurface = &GetGDISurface;
+		vtable.SetCooperativeLevel = &SetCooperativeLevel;
 		vtable.WaitForVerticalBlank = &WaitForVerticalBlank;
 
 		if constexpr (std::is_same_v<Vtable, IDirectDraw4Vtbl> || std::is_same_v<Vtable, IDirectDraw7Vtbl>)
@@ -142,6 +192,42 @@ namespace DDraw
 			return pf;
 		}
 
+		LRESULT handleActivateApp(bool isActivated, std::function<LRESULT()> callOrigWndProc)
+		{
+			LOG_FUNC("handleActivateApp", isActivated, callOrigWndProc);
+			if (Config::Settings::AltTabFix::KEEPVIDMEM != Config::altTabFix.get())
+			{
+				return LOG_RESULT(callOrigWndProc());
+			}
+
+			DDraw::ScopedThreadLock lock;
+			std::set<void*> surfacesToRestore;
+			TagSurface::forEachDirectDraw([&](CompatRef<IDirectDraw7> dd)
+				{
+					dd->EnumSurfaces(&dd, DDENUMSURFACES_DOESEXIST | DDENUMSURFACES_ALL, nullptr,
+						&surfacesToRestore, &setSurfaceLostFlag);
+				});
+
+			LRESULT result = callOrigWndProc();
+
+			TagSurface::forEachDirectDraw([&](CompatRef<IDirectDraw7> dd)
+				{
+					dd->EnumSurfaces(&dd, DDENUMSURFACES_DOESEXIST | DDENUMSURFACES_ALL, nullptr,
+						&surfacesToRestore, &restoreSurfaceLostFlag);
+				});
+
+			if (isActivated)
+			{
+				auto realPrimary(DDraw::RealPrimarySurface::getSurface());
+				if (realPrimary)
+				{
+					realPrimary->Restore(realPrimary);
+				}
+			}
+
+			return LOG_RESULT(result);
+		}
+
 		void onCreate(GUID* guid, CompatRef<IDirectDraw7> dd)
 		{
 			static std::map<LUID, CompatWeakPtr<IDirectDraw7>> repositories;
@@ -155,7 +241,7 @@ namespace DDraw
 				{
 					return;
 				}
-				repo->SetCooperativeLevel(repo, nullptr, DDSCL_NORMAL);
+				repo.get()->lpVtbl->SetCooperativeLevel(repo, nullptr, DDSCL_NORMAL);
 				it = repositories.insert({ adapterInfo.luid, repo }).first;
 				repo.detach();
 			}
diff --git a/DDrawCompat/DDraw/DirectDraw.h b/DDrawCompat/DDraw/DirectDraw.h
index d924044..ebe8caf 100644
--- a/DDrawCompat/DDraw/DirectDraw.h
+++ b/DDrawCompat/DDraw/DirectDraw.h
@@ -1,5 +1,7 @@
 #pragma once
 
+#include <functional>
+
 #include <ddraw.h>
 
 #include <Common/CompatPtr.h>
@@ -11,9 +13,16 @@ namespace DDraw
 	{
 		DDSURFACEDESC2 getDisplayMode(CompatRef<IDirectDraw7> dd);
 		DDPIXELFORMAT getRgbPixelFormat(DWORD bpp);
+		LRESULT handleActivateApp(bool isActivated, std::function<LRESULT()> callOrigWndProc);
 		void onCreate(GUID* guid, CompatRef<IDirectDraw7> dd);
 		void suppressEmulatedDirectDraw(GUID*& guid);
 
+		template <typename TDirectDraw>
+		void* getDdObject(TDirectDraw& dd)
+		{
+			return reinterpret_cast<void**>(&dd)[1];
+		}
+
 		template <typename TDirectDraw>
 		HWND* getDeviceWindowPtr(TDirectDraw& dd)
 		{
diff --git a/DDrawCompat/DDraw/DirectDrawSurface.h b/DDrawCompat/DDraw/DirectDrawSurface.h
index 614362c..7853934 100644
--- a/DDrawCompat/DDraw/DirectDrawSurface.h
+++ b/DDrawCompat/DDraw/DirectDrawSurface.h
@@ -13,6 +13,18 @@ namespace DDraw
 	{
 		std::vector<CompatPtr<IDirectDrawSurface7>> getAllAttachedSurfaces(CompatRef<IDirectDrawSurface7> surface);
 
+		template <typename TSurface>
+		void* getSurfaceObject(TSurface& surface)
+		{
+			return reinterpret_cast<void**>(&surface)[1];
+		}
+
+		template <typename TSurface>
+		DWORD& getFlags(TSurface& surface)
+		{
+			return reinterpret_cast<DWORD**>(&surface)[1][7];
+		}
+
 		template <typename TSurface>
 		HANDLE getRuntimeResourceHandle(TSurface& surface)
 		{
diff --git a/DDrawCompat/DDraw/Surfaces/TagSurface.cpp b/DDrawCompat/DDraw/Surfaces/TagSurface.cpp
new file mode 100644
index 0000000..dc0ed95
--- /dev/null
+++ b/DDrawCompat/DDraw/Surfaces/TagSurface.cpp
@@ -0,0 +1,56 @@
+#include <map>
+
+#include <DDraw/DirectDraw.h>
+#include <DDraw/Surfaces/TagSurface.h>
+
+namespace
+{
+	std::map<void*, DDraw::TagSurface*> g_ddObjects;
+}
+
+namespace DDraw
+{
+	HRESULT TagSurface::create(CompatRef<IDirectDraw> dd)
+	{
+		auto ddObject = DDraw::DirectDraw::getDdObject(dd.get());
+		if (g_ddObjects.find(ddObject) != g_ddObjects.end())
+		{
+			return DD_OK;
+		}
+
+		DDSURFACEDESC desc = {};
+		desc.dwSize = sizeof(desc);
+		desc.dwFlags = DDSD_WIDTH | DDSD_HEIGHT | DDSD_CAPS;
+		desc.dwWidth = 1;
+		desc.dwHeight = 1;
+		desc.ddsCaps.dwCaps = DDSCAPS_OFFSCREENPLAIN | DDSCAPS_SYSTEMMEMORY;
+
+		auto privateData(std::make_unique<TagSurface>(desc.ddsCaps.dwCaps, ddObject));
+		g_ddObjects[ddObject] = privateData.get();
+
+		IDirectDrawSurface* surface = nullptr;
+		return Surface::create(dd, desc, surface, std::move(privateData));
+	}
+
+	void TagSurface::forEachDirectDraw(std::function<void(CompatRef<IDirectDraw7>)> callback)
+	{
+		struct DirectDrawInterface
+		{
+			const void* vtable;
+			void* ddObject;
+			DirectDrawInterface* next;
+			DWORD refCount;
+		};
+
+		for (auto ddObj : g_ddObjects)
+		{
+			DirectDrawInterface intf = { &CompatVtable<IDirectDraw7Vtbl>::s_origVtable, ddObj.first, nullptr, 1 };
+			callback(CompatRef<IDirectDraw7>(reinterpret_cast<IDirectDraw7&>(intf)));
+		}
+	}
+
+	TagSurface::~TagSurface()
+	{
+		g_ddObjects.erase(m_ddObject);
+	}
+}
diff --git a/DDrawCompat/DDraw/Surfaces/TagSurface.h b/DDrawCompat/DDraw/Surfaces/TagSurface.h
new file mode 100644
index 0000000..3778d6f
--- /dev/null
+++ b/DDrawCompat/DDraw/Surfaces/TagSurface.h
@@ -0,0 +1,23 @@
+#pragma once
+
+#include <ddraw.h>
+#include <functional>
+
+#include <Common/CompatRef.h>
+#include <DDraw/Surfaces/Surface.h>
+
+namespace DDraw
+{
+	class TagSurface : public Surface
+	{
+	public:
+		TagSurface(DWORD origCaps, void* ddObject) : Surface(origCaps), m_ddObject(ddObject) {}
+		virtual ~TagSurface() override;
+
+		static HRESULT create(CompatRef<IDirectDraw> dd);
+		static void forEachDirectDraw(std::function<void(CompatRef<IDirectDraw7>)> callback);
+
+	private:
+		void* m_ddObject;
+	};
+}
diff --git a/DDrawCompat/DDrawCompat.vcxproj b/DDrawCompat/DDrawCompat.vcxproj
index fcb9610..c100f96 100644
--- a/DDrawCompat/DDrawCompat.vcxproj
+++ b/DDrawCompat/DDrawCompat.vcxproj
@@ -218,6 +218,7 @@
     <ClInclude Include="Config\Parser.h" />
     <ClInclude Include="Config\Setting.h" />
     <ClInclude Include="Config\Settings\AlternatePixelCenter.h" />
+    <ClInclude Include="Config\Settings\AltTabFix.h" />
     <ClInclude Include="Config\Settings\Antialiasing.h" />
     <ClInclude Include="Config\Settings\ConfigHotKey.h" />
     <ClInclude Include="Config\Settings\CpuAffinity.h" />
@@ -277,6 +278,7 @@
     <ClInclude Include="DDraw\Surfaces\PrimarySurfaceImpl.h" />
     <ClInclude Include="DDraw\Surfaces\Surface.h" />
     <ClInclude Include="DDraw\Surfaces\SurfaceImpl.h" />
+    <ClInclude Include="DDraw\Surfaces\TagSurface.h" />
     <ClInclude Include="DDraw\Types.h" />
     <ClInclude Include="DDraw\IReleaseNotifier.h" />
     <ClInclude Include="DDraw\RealPrimarySurface.h" />
@@ -399,6 +401,7 @@
     <ClCompile Include="DDraw\Surfaces\PrimarySurfaceImpl.cpp" />
     <ClCompile Include="DDraw\Surfaces\Surface.cpp" />
     <ClCompile Include="DDraw\Surfaces\SurfaceImpl.cpp" />
+    <ClCompile Include="DDraw\Surfaces\TagSurface.cpp" />
     <ClCompile Include="Direct3d\Direct3d.cpp" />
     <ClCompile Include="Direct3d\Direct3dDevice.cpp" />
     <ClCompile Include="Direct3d\Direct3dExecuteBuffer.cpp" />
diff --git a/DDrawCompat/DDrawCompat.vcxproj.filters b/DDrawCompat/DDrawCompat.vcxproj.filters
index 0c64677..576e100 100644
--- a/DDrawCompat/DDrawCompat.vcxproj.filters
+++ b/DDrawCompat/DDrawCompat.vcxproj.filters
@@ -546,6 +546,12 @@
     <ClInclude Include="Config\Settings\VSync.h">
       <Filter>Header Files\Config\Settings</Filter>
     </ClInclude>
+    <ClInclude Include="DDraw\Surfaces\TagSurface.h">
+      <Filter>Header Files\DDraw\Surfaces</Filter>
+    </ClInclude>
+    <ClInclude Include="Config\Settings\AltTabFix.h">
+      <Filter>Header Files\Config\Settings</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="Gdi\Gdi.cpp">
@@ -863,6 +869,9 @@
     <ClCompile Include="Config\Settings\VSync.cpp">
       <Filter>Source Files\Config\Settings</Filter>
     </ClCompile>
+    <ClCompile Include="DDraw\Surfaces\TagSurface.cpp">
+      <Filter>Source Files\DDraw\Surfaces</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ResourceCompile Include="DDrawCompat.rc">
diff --git a/DDrawCompat/Gdi/WinProc.cpp b/DDrawCompat/Gdi/WinProc.cpp
index c1226da..946da25 100644
--- a/DDrawCompat/Gdi/WinProc.cpp
+++ b/DDrawCompat/Gdi/WinProc.cpp
@@ -7,6 +7,7 @@
 #include <Common/Log.h>
 #include <Common/ScopedSrwLock.h>
 #include <Dll/Dll.h>
+#include <DDraw/DirectDraw.h>
 #include <DDraw/RealPrimarySurface.h>
 #include <DDraw/Surfaces/PrimarySurface.h>
 #include <Gdi/CompatDc.h>
@@ -105,7 +106,17 @@ namespace
 			break;
 		}
 
-		LRESULT result = callWindowProc(wndProc, hwnd, uMsg, wParam, lParam);
+		LRESULT result = 0;
+		if (WM_ACTIVATEAPP == uMsg && Dll::g_origDDrawModule == Compat::getModuleHandleFromAddress(
+			reinterpret_cast<void*>(GetWindowLongA(hwnd, GWL_WNDPROC))))
+		{
+			result = DDraw::DirectDraw::handleActivateApp(wParam, [=]() {
+				return callWindowProc(wndProc, hwnd, uMsg, wParam, lParam); });
+		}
+		else
+		{
+			result = callWindowProc(wndProc, hwnd, uMsg, wParam, lParam);
+		}
 
 		switch (uMsg)
 		{