Keyboard:

. reverted default so that ALT+TAB is not hooked (#556)
. reverted default so that ALT GR's fake LCONTROL is not hooked (#558)
. added new switches: -hook-alt-tab and -hook-altgr-control to support hooking these key combo's (#556)

HookFilter/HookFilter.cpp

@@ -1,6 +1,8 @@
 #include <windows.h>
 
 static HWND g_hFrameWindow = (HWND)0;
+static bool g_bHookAltTab = false;
+static bool g_bHookAltGrControl = false;
 
 // NB. __stdcall (or WINAPI) and extern "C":
 // . symbol is decorated as _<symbol>@bytes
@@ -27,13 +29,13 @@ extern "C" __declspec(dllexport) LRESULT CALLBACK LowLevelKeyboardProc(
 		// . For: Microsoft PS/2/Win7-64, VAIO laptop/Win7-64, Microsoft USB/Win10-64
 		// NB. WM_KEYDOWN also includes a 9/10-bit? scanCode: LCONTROL=0x1D, RCONTROL=0x11D, RMENU=0x1D(not 0x21D)
 		// . Can't suppress in app, since scanCode is not >= 0x200
-		if (pKbdLlHookStruct->vkCode == VK_LCONTROL && pKbdLlHookStruct->scanCode >= 0x200)	// GH#558
+		if (g_bHookAltGrControl && pKbdLlHookStruct->vkCode == VK_LCONTROL && pKbdLlHookStruct->scanCode >= 0x200)	// GH#558
 		{
 			suppress = true;
 		}
 
 		// Suppress alt-tab
-		if (pKbdLlHookStruct->vkCode == VK_TAB && (pKbdLlHookStruct->flags & LLKHF_ALTDOWN))
+		if (g_bHookAltTab && pKbdLlHookStruct->vkCode == VK_TAB && (pKbdLlHookStruct->flags & LLKHF_ALTDOWN))
 		{
 			PostMessage(g_hFrameWindow, newMsg, VK_TAB, newlParam);
 			suppress = true;
@@ -69,7 +71,9 @@ extern "C" __declspec(dllexport) LRESULT CALLBACK LowLevelKeyboardProc(
 	return CallNextHookEx(0/*parameter is ignored*/, nCode, wParam, lParam);
 }
 
-extern "C" __declspec(dllexport) void __cdecl RegisterHWND(HWND hWnd)
+extern "C" __declspec(dllexport) void __cdecl RegisterHWND(HWND hWnd, bool bHookAltTab, bool bHookAltGrControl)
 {
 	g_hFrameWindow = hWnd;
+	g_bHookAltTab = bHookAltTab;
+	g_bHookAltGrControl = bHookAltGrControl;
 }

source/Applewin.cpp

@@ -79,6 +79,8 @@ TCHAR     g_sDebugDir  [MAX_PATH] = TEXT(""); // TODO: Not currently used
 TCHAR     g_sScreenShotDir[MAX_PATH] = TEXT(""); // TODO: Not currently used
 bool      g_bCapturePrintScreenKey = true;
 static bool g_bHookSystemKey = true;
+static bool g_bHookAltTab = false;
+static bool g_bHookAltGrControl = false;
 
 TCHAR     g_sCurrentDir[MAX_PATH] = TEXT(""); // Also Starting Dir.  Debugger uses this when load/save
 bool      g_bRestart = false;
@@ -171,6 +173,11 @@ void SetLoadedSaveStateFlag(const bool bFlag)
 	g_bLoadedSaveState = bFlag;
 }
 
+bool GetHookAltGrControl(void)
+{
+	return g_bHookAltGrControl;
+}
+
 static void ResetToLogoMode(void)
 {
 	g_nAppMode = MODE_LOGO;
@@ -882,10 +889,10 @@ static bool HookFilterForKeyboard()
 
 	_ASSERT(g_hFrameWindow);
 
-	typedef void (*RegisterHWNDProc)(HWND);
+	typedef void (*RegisterHWNDProc)(HWND, bool, bool);
 	RegisterHWNDProc RegisterHWND = (RegisterHWNDProc) GetProcAddress(g_hinstDLL, "RegisterHWND");
 	if (RegisterHWND)
-		RegisterHWND(g_hFrameWindow);
+		RegisterHWND(g_hFrameWindow, g_bHookAltTab, g_bHookAltGrControl);
 
 	HOOKPROC hkprcLowLevelKeyboardProc = (HOOKPROC) GetProcAddress(g_hinstDLL, "LowLevelKeyboardProc");
 
@@ -1294,6 +1301,14 @@ int APIENTRY WinMain(HINSTANCE passinstance, HINSTANCE, LPSTR lpCmdLine, int)
 		{
 			g_bHookSystemKey = false;
 		}
+		else if (strcmp(lpCmdLine, "-hook-alt-tab") == 0)			// GH#556
+		{
+			g_bHookAltTab = true;
+		}
+		else if (strcmp(lpCmdLine, "-hook-altgr-control") == 0)		// GH#556
+		{
+			g_bHookAltGrControl = true;
+		}
 		else if (strcmp(lpCmdLine, "-spkr-inc") == 0)
 		{
 			lpCmdLine = GetCurrArg(lpNextArg);

source/Applewin.h

@@ -30,6 +30,7 @@ extern HINSTANCE  g_hInstance;
 extern AppMode_e g_nAppMode;
 bool GetLoadedSaveStateFlag(void);
 void SetLoadedSaveStateFlag(const bool bFlag);
+bool GetHookAltGrControl(void);
 
 extern TCHAR      g_sProgramDir[MAX_PATH];
 extern TCHAR      g_sCurrentDir[MAX_PATH];

source/Keyboard.cpp

@@ -319,7 +319,7 @@ void KeybQueueKeypress (WPARAM key, Keystroke_e bASCII)
 				{
 					if ( (GetKeyState(VK_SHIFT) >= 0) && !g_bCapsLock )
 						newKey += 'a' - 'A';	// convert to lowercase key
-					else if (GetKeyState(VK_CONTROL) < 0)
+					else if (GetHookAltGrControl() && GetKeyState(VK_CONTROL) < 0)
 						newKey -= 'A' - 1;		// convert to control-key
 				}