diff --git a/src/emu/debug/debugcpu.c b/src/emu/debug/debugcpu.c
index 742b22f49f3..511b3198403 100644
--- a/src/emu/debug/debugcpu.c
+++ b/src/emu/debug/debugcpu.c
@@ -2000,8 +2000,9 @@ static void compute_debug_flags(running_device *device)
 	running_machine *machine = device->machine;
 	debugcpu_private *global = machine->debugcpu_data;
 
-	/* clear out all global flags by default */
-	machine->debug_flags = DEBUG_FLAG_ENABLED;
+	/* clear out global flags by default, keep DEBUG_FLAG_OSD_ENABLED */
+	machine->debug_flags &= DEBUG_FLAG_OSD_ENABLED;
+	machine->debug_flags |= DEBUG_FLAG_ENABLED;
 
 	/* if we are ignoring this CPU, or if events are pending, we're done */
 	if ((info->flags & DEBUG_FLAG_OBSERVING) == 0 || mame_is_scheduled_event_pending(machine) || mame_is_save_or_load_pending(machine))
diff --git a/src/emu/mame.c b/src/emu/mame.c
index 69aa08b0790..6d679764d65 100644
--- a/src/emu/mame.c
+++ b/src/emu/mame.c
@@ -1317,7 +1317,7 @@ running_machine::running_machine(const game_driver *driver)
 
 		/* fetch core options */
 		sample_rate = options_get_int(mame_options(), OPTION_SAMPLERATE);
-		debug_flags = options_get_bool(mame_options(), OPTION_DEBUG) ? (DEBUG_FLAG_ENABLED | DEBUG_FLAG_CALL_HOOK) : 0;
+		debug_flags = options_get_bool(mame_options(), OPTION_DEBUG) ? (DEBUG_FLAG_ENABLED | DEBUG_FLAG_OSD_ENABLED | DEBUG_FLAG_CALL_HOOK) : 0;
 	}
 	catch (std::bad_alloc &)
 	{
diff --git a/src/emu/mame.h b/src/emu/mame.h
index 2936c7a7e1c..e680846465c 100644
--- a/src/emu/mame.h
+++ b/src/emu/mame.h
@@ -62,6 +62,7 @@ enum
 #define DEBUG_FLAG_WPW_PROGRAM	0x00000100		/* watchpoints are enabled for PROGRAM memory writes */
 #define DEBUG_FLAG_WPW_DATA		0x00000200		/* watchpoints are enabled for DATA memory writes */
 #define DEBUG_FLAG_WPW_IO		0x00000400		/* watchpoints are enabled for IO memory writes */
+#define DEBUG_FLAG_OSD_ENABLED	0x00001000		/* The OSD debugger is enabled */
 
 
 /* MESS vs. MAME abstractions */
diff --git a/src/osd/sdl/input.c b/src/osd/sdl/input.c
index 97fadf0c44e..f1271586406 100644
--- a/src/osd/sdl/input.c
+++ b/src/osd/sdl/input.c
@@ -1118,7 +1118,7 @@ void sdlinput_init(running_machine *machine)
 	// register the mice
 	sdlinput_register_mice(machine);
 
-	if (machine->debug_flags & DEBUG_FLAG_ENABLED)
+	if (machine->debug_flags & DEBUG_FLAG_OSD_ENABLED)
 	{
 		mame_printf_warning("Debug Build: Disabling input grab for -debug\n");
 		mouse_enabled = 0;
diff --git a/src/osd/sdl/sdlmain.c b/src/osd/sdl/sdlmain.c
index a0d45555363..2538b5b1eb3 100644
--- a/src/osd/sdl/sdlmain.c
+++ b/src/osd/sdl/sdlmain.c
@@ -541,7 +541,7 @@ void osd_init(running_machine *machine)
 	defines_verbose();
 
 	if (!SDLMAME_HAS_DEBUGGER)
-		if (options_get_bool(mame_options(), OPTION_DEBUG))
+		if (machine->debug_flags & DEBUG_FLAG_OSD_ENABLED)
 		{
 			mame_printf_error("sdlmame: -debug not supported on X11-less builds\n\n");
 			osd_exit(machine);
diff --git a/src/osd/sdl/video.c b/src/osd/sdl/video.c
index 3bf06c33fcb..94bff57aae0 100644
--- a/src/osd/sdl/video.c
+++ b/src/osd/sdl/video.c
@@ -354,7 +354,7 @@ void osd_update(running_machine *machine, int skip_redraw)
 	sdlinput_poll(machine);
 	check_osd_inputs(machine);
 
-	if (machine->debug_flags & DEBUG_FLAG_ENABLED)
+	if ((machine->debug_flags & DEBUG_FLAG_OSD_ENABLED) != 0)
 		debugwin_update_during_game(machine);
 }
 
@@ -635,7 +635,7 @@ static void extract_video_config(running_machine *machine)
 	#endif
 
 
-	if (options_get_bool(mame_options(), OPTION_DEBUG))
+	if (machine->debug_flags & DEBUG_FLAG_OSD_ENABLED)
 		video_config.windowed = TRUE;
 
 	stemp = options_get_string(mame_options(), SDLOPTION_EFFECT);
diff --git a/src/osd/sdl/window.c b/src/osd/sdl/window.c
index 5ce119b21b6..0087e82ba13 100644
--- a/src/osd/sdl/window.c
+++ b/src/osd/sdl/window.c
@@ -510,7 +510,7 @@ static OSDWORK_CALLBACK( sdlwindow_toggle_full_screen_wt )
 	ASSERT_WINDOW_THREAD();
 
 	// if we are in debug mode, never go full screen
-	if (options_get_bool(mame_options(), OPTION_DEBUG))
+	if (window->machine->debug_flags & DEBUG_FLAG_OSD_ENABLED)
 		return NULL;
 
 	// If we are going fullscreen (leaving windowed) remember our windowed size
@@ -642,7 +642,7 @@ static void sdlwindow_update_cursor_state(running_machine *machine, sdl_window_i
 #if (SDL_VERSION_ATLEAST(1,3,0))
 	// do not do mouse capture if the debugger's enabled to avoid
 	// the possibility of losing control
-	if (!options_get_bool(mame_options(), OPTION_DEBUG))
+	if (!(machine->debug_flags & DEBUG_FLAG_OSD_ENABLED))
 	{
 		//FIXME: SDL1.3: really broken: the whole SDL code
 		//       will only work correct with relative mouse movements ...
@@ -665,7 +665,7 @@ static void sdlwindow_update_cursor_state(running_machine *machine, sdl_window_i
 #else
 	// do not do mouse capture if the debugger's enabled to avoid
 	// the possibility of losing control
-	if (!options_get_bool(mame_options(), OPTION_DEBUG))
+	if (!(machine->debug_flags & DEBUG_FLAG_OSD_ENABLED))
 	{
 		if ( window->fullscreen || sdlinput_should_hide_mouse(machine) )
 		{
diff --git a/src/osd/windows/video.c b/src/osd/windows/video.c
index db9cfb012e6..48c99b378f3 100644
--- a/src/osd/windows/video.c
+++ b/src/osd/windows/video.c
@@ -137,7 +137,7 @@ void winvideo_init(running_machine *machine)
 		SetForegroundWindow(win_window_list->hwnd);
 
 	// possibly create the debug window, but don't show it yet
-	if (options_get_bool(mame_options(), OPTION_DEBUG))
+	if (machine->debug_flags & DEBUG_FLAG_OSD_ENABLED)
 		debugwin_init_windows();
 }
 
@@ -406,7 +406,7 @@ static void extract_video_config(running_machine *machine)
 	video_config.numscreens    = options_get_int(mame_options(), WINOPTION_NUMSCREENS);
 
 	// if we are in debug mode, never go full screen
-	if (options_get_bool(mame_options(), OPTION_DEBUG))
+	if (machine->debug_flags & DEBUG_FLAG_OSD_ENABLED)
 		video_config.windowed = TRUE;
 	stemp                      = options_get_string(mame_options(), WINOPTION_EFFECT);
 	if (strcmp(stemp, "none") != 0)
diff --git a/src/osd/windows/window.c b/src/osd/windows/window.c
index 70dc43ee43d..61d75e5ec34 100644
--- a/src/osd/windows/window.c
+++ b/src/osd/windows/window.c
@@ -301,7 +301,7 @@ static void winwindow_exit(running_machine *machine)
 	assert(GetCurrentThreadId() == main_threadid);
 
 	// possibly kill the debug window
-	if (options_get_bool(mame_options(), OPTION_DEBUG))
+	if (machine->debug_flags & DEBUG_FLAG_OSD_ENABLED)
 		debugwin_destroy_windows();
 
 	// free all the windows
@@ -386,7 +386,7 @@ void winwindow_process_events(running_machine *machine, int ingame)
 	assert(GetCurrentThreadId() == main_threadid);
 
 	// if we're running, disable some parts of the debugger
-	if (ingame && (machine->debug_flags & DEBUG_FLAG_ENABLED) != 0)
+	if (ingame && (machine->debug_flags & DEBUG_FLAG_OSD_ENABLED) != 0)
 		debugwin_update_during_game(machine);
 
 	// remember the last time we did this
@@ -514,8 +514,9 @@ void winwindow_toggle_full_screen(void)
 	assert(GetCurrentThreadId() == main_threadid);
 
 	// if we are in debug mode, never go full screen
-	if (options_get_bool(mame_options(), OPTION_DEBUG))
-		return;
+	for (window = win_window_list; window != NULL; window = window->next)
+		if (window->machine->debug_flags & DEBUG_FLAG_OSD_ENABLED)
+			return;
 
 	// toggle the window mode
 	video_config.windowed = !video_config.windowed;
diff --git a/src/osd/windows/winmain.c b/src/osd/windows/winmain.c
index 8e3176dc034..ee5b3c4ce8f 100644
--- a/src/osd/windows/winmain.c
+++ b/src/osd/windows/winmain.c
@@ -339,7 +339,7 @@ void osd_init(running_machine *machine)
 	const char *stemp;
 
 	// thread priority
-	if (!options_get_bool(mame_options(), OPTION_DEBUG))
+	if (!(machine->debug_flags & DEBUG_FLAG_OSD_ENABLED))
 		SetThreadPriority(GetCurrentThread(), options_get_int(mame_options(), WINOPTION_PRIORITY));
 
 	// ensure we get called on the way out