diff --git a/include/nana/gui/detail/general_events.hpp b/include/nana/gui/detail/general_events.hpp
index 5992f1a0..72b4cbf3 100644
--- a/include/nana/gui/detail/general_events.hpp
+++ b/include/nana/gui/detail/general_events.hpp
@@ -1,7 +1,7 @@
 /**
 *	Definition of General Events
 *	Nana C++ Library(http://www.nanapro.org)
-*	Copyright(C) 2003-2016 Jinhao(cnjinhao@hotmail.com)
+*	Copyright(C) 2003-2018 Jinhao(cnjinhao@hotmail.com)
 *
 *	Distributed under the Boost Software License, Version 1.0.
 *	(See accompanying file LICENSE_1_0.txt or copy at
@@ -460,8 +460,9 @@ namespace nana
 		::nana::window window_handle;	///< A handle to the event window
 		mutable wchar_t key;	///< the key corresponding to the key pressed
 		mutable bool ignore;	    ///< this member is only available for key_char event, set 'true' to ignore the input.
-		bool ctrl;	                ///< keyboard Ctrl is pressed?
-		bool shift;	                ///< keyboard Shift is pressed
+		bool alt;					///< it is set to indicate the modifier key Alt just prior to the event.
+		bool ctrl;	                ///< it is set to indicate the modifier key Ctrl just prior to the event.
+		bool shift;	                ///< it is set to indicate the modifier key Shift just prior to the event.
 	};
 
 	struct arg_move : public event_arg
diff --git a/source/gui/detail/bedrock_posix.cpp b/source/gui/detail/bedrock_posix.cpp
index ac297366..131d42de 100644
--- a/source/gui/detail/bedrock_posix.cpp
+++ b/source/gui/detail/bedrock_posix.cpp
@@ -223,6 +223,7 @@ namespace detail
 	{
 		XKeyEvent xkey;
 		nana::detail::platform_spec::instance().read_keystate(xkey);
+		arg.alt = (xkey.state & Mod1Mask);
 		arg.ctrl = (xkey.state & ControlMask);
 		arg.shift = (xkey.state & ShiftMask);
 	}
diff --git a/source/gui/detail/bedrock_windows.cpp b/source/gui/detail/bedrock_windows.cpp
index 9618c47e..96aaed8f 100644
--- a/source/gui/detail/bedrock_windows.cpp
+++ b/source/gui/detail/bedrock_windows.cpp
@@ -1622,6 +1622,7 @@ namespace detail
 
 	void bedrock::get_key_state(arg_keyboard& kb)
 	{
+		kb.alt = (0 != (::GetKeyState(VK_MENU) & 0x80));
 		kb.ctrl = (0 != (::GetKeyState(VK_CONTROL) & 0x80));
 		kb.shift = (0 != (::GetKeyState(VK_SHIFT) & 0x80));
 	}