Fix #4251 macOS mouse grab issue (#4298)

Source/utils/display.cpp

@@ -243,11 +243,14 @@ bool SpawnWindow(const char *lpWindowName)
 		flags |= SDL_WINDOW_FULLSCREEN;
 	}
 
-	if (*sgOptions.Gameplay.grabInput) {
-		flags |= SDL_WINDOW_INPUT_GRABBED;
-	}
-
 	ghMainWnd = SDL_CreateWindow(lpWindowName, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, windowSize.width, windowSize.height, flags);
+
+	// Note: https://github.com/libsdl-org/SDL/issues/962
+	// This is a solution to a problem related to SDL mouse grab.
+	// See https://github.com/diasurgical/devilutionX/issues/4251
+	if (ghMainWnd != nullptr)
+		SDL_SetWindowGrab(ghMainWnd, *sgOptions.Gameplay.grabInput ? SDL_TRUE : SDL_FALSE);
+
 #endif
 	if (ghMainWnd == nullptr) {
 		ErrSdl();