diff --git a/desmume/src/NDSSystem.cpp b/desmume/src/NDSSystem.cpp
index 586622874..ececa8b76 100644
--- a/desmume/src/NDSSystem.cpp
+++ b/desmume/src/NDSSystem.cpp
@@ -1719,14 +1719,14 @@ void NDS_exec(s32 nb)
 			// but by a 22 mhz oscillator.
 
 			//zeromus way: i did this in a rush and it is not perfect, but it is more like what it needs to be
-			nds.wifiCycle += (nds.ARM7Cycle-nds7old)<<16;
-			while(nds.wifiCycle > 0)
-			{
-				nds.wifiCycle -= 946453; //22*22000000*65536/ARM7_CLOCK;
-				WIFI_usTrigger(&wifiMac);
-				WIFI_SoftAP_usTrigger(&wifiMac);
-			}
-			
+			//nds.wifiCycle += (nds.ARM7Cycle-nds7old)<<16;
+			//while(nds.wifiCycle > 0)
+			//{
+			//	nds.wifiCycle -= 946453; //22*22000000*65536/ARM7_CLOCK;
+			//	WIFI_usTrigger(&wifiMac);
+			//	WIFI_SoftAP_usTrigger(&wifiMac);
+			//}
+			//
 			//luigi's way>
 			/*if(nds7old < nds.ARM7Cycle)
 			{
diff --git a/desmume/src/windows/main.cpp b/desmume/src/windows/main.cpp
index 3681f6828..c144364db 100644
--- a/desmume/src/windows/main.cpp
+++ b/desmume/src/windows/main.cpp
@@ -199,7 +199,8 @@ int WndY = 0;
 
 int ScreenGap = 0;
 extern HWND RamSearchHWnd;
-
+static BOOL lostFocusPause = TRUE;
+static BOOL lastPauseFromLostFocus = FALSE;
 static int FrameLimit = 1;
 
 //=========================== view tools
@@ -1647,6 +1648,7 @@ int _main()
 	FrameLimit = GetPrivateProfileInt("FrameLimit", "FrameLimit", 1, IniName);
 	CommonSettings.showGpu.main = GetPrivateProfileInt("Display", "MainGpu", 1, IniName) != 0;
 	CommonSettings.showGpu.sub = GetPrivateProfileInt("Display", "SubGpu", 1, IniName) != 0;
+	lostFocusPause = GetPrivateProfileInt("Focus", "BackgroundPause", 0, IniName);
 
 	
 	//Get Ram-Watch values
@@ -2501,8 +2503,16 @@ int HandleKeyMessage(WPARAM wParam, LPARAM lParam, int modifiers)
 	return 1;
 }
 
+static void Unpause()
+{
+	lastPauseFromLostFocus = FALSE;
+	if (emu_paused) NDS_UnPause();
+	emu_paused = 0;
+}
+
 void Pause()
 {
+	lastPauseFromLostFocus = FALSE;
 	if (emu_paused) NDS_UnPause();
 	else NDS_Pause();
 	emu_paused ^= 1;
@@ -2697,6 +2707,8 @@ LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM
 
 			//Language selection
 
+			MainWindow->checkMenu(IDC_BACKGROUNDPAUSE, MF_BYCOMMAND | ((lostFocusPause)?MF_CHECKED:MF_UNCHECKED));
+
 			//Save type
 			const int savelist[] = {IDC_SAVETYPE1,IDC_SAVETYPE2,IDC_SAVETYPE3,IDC_SAVETYPE4,IDC_SAVETYPE5,IDC_SAVETYPE6,IDC_SAVETYPE7};
 			for(int i=0;i<7;i++) MainWindow->checkMenu(savelist[i], MF_BYCOMMAND | MF_UNCHECKED);
@@ -2773,6 +2785,23 @@ LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM
 		UpdateWndRects(hwnd);
 		return 0;
 	}
+
+	case WM_KILLFOCUS:
+		if(lostFocusPause) {
+			if(!emu_paused) {
+				Pause();
+				lastPauseFromLostFocus = TRUE;
+			}
+		}
+		return 0;
+	case WM_SETFOCUS:
+		if(lostFocusPause) {
+			if(lastPauseFromLostFocus) {
+				Unpause();
+			}
+		}
+		return 0;
+
 	case WM_SIZING:
 		{
 			InvalidateRect(hwnd, NULL, FALSE); UpdateWindow(hwnd);
@@ -3393,6 +3422,11 @@ LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM
 				SetForegroundWindow(RamWatchHWnd);
 			return 0;
 
+		case IDC_BACKGROUNDPAUSE:
+			lostFocusPause = !lostFocusPause;
+			WritePrivateProfileInt("Focus", "BackgroundPause", (int)lostFocusPause, IniName);
+			return 0;
+
 		case IDC_SAVETYPE1: backup_setManualBackupType(0); return 0;
 		case IDC_SAVETYPE2: backup_setManualBackupType(1); return 0;   
 		case IDC_SAVETYPE3: backup_setManualBackupType(2); return 0;   
diff --git a/desmume/src/windows/resource.h b/desmume/src/windows/resource.h
index fd017e284..6a8fbdae5 100644
--- a/desmume/src/windows/resource.h
+++ b/desmume/src/windows/resource.h
@@ -100,6 +100,7 @@
 #define IDC_8_BIT                       302
 #define IDC_16_BIT                      303
 #define IDC_32_BIT                      304
+#define IDC_BACKGROUNDPAUSE             305
 #define IDC_DES_BOX                     402
 #define IDC_R0                          403
 #define IDC_R1                          404
@@ -613,6 +614,7 @@
 #define IDM_ABOUT                       40003
 #define IDM_EMULATIONSETTINGS           40004
 #define IDC_FRAMELIMIT                  40005
+#define ID_CONFIG_PAUSEWHENFOCUSLOST    40005
 #define IDC_WINDOW1_5X                  40006
 #define IDM_WIFISETTINGS                40007
 #define IDM_ALWAYS_ON_TOP               40008
@@ -727,7 +729,7 @@
 #ifdef APSTUDIO_INVOKED
 #ifndef APSTUDIO_READONLY_SYMBOLS
 #define _APS_NEXT_RESOURCE_VALUE        105
-#define _APS_NEXT_COMMAND_VALUE         40003
+#define _APS_NEXT_COMMAND_VALUE         40008
 #define _APS_NEXT_CONTROL_VALUE         1001
 #define _APS_NEXT_SYMED_VALUE           101
 #endif
diff --git a/desmume/src/windows/resources.rc b/desmume/src/windows/resources.rc
index bd7fb42bf..30896884a 100644
Binary files a/desmume/src/windows/resources.rc and b/desmume/src/windows/resources.rc differ