diff --git a/include/nana/detail/linux_X11/msg_packet.hpp b/include/nana/detail/linux_X11/msg_packet.hpp
index b1fc3dec..ea24091f 100644
--- a/include/nana/detail/linux_X11/msg_packet.hpp
+++ b/include/nana/detail/linux_X11/msg_packet.hpp
@@ -22,7 +22,7 @@ namespace detail
 				Window window;
 				int x;
 				int y;
-				std::vector<nana::string> * files;
+				std::vector<std::string> * files;
 			}mouse_drop;
 		}u;
 	};
diff --git a/include/nana/detail/linux_X11/platform_spec.hpp b/include/nana/detail/linux_X11/platform_spec.hpp
index 44a73a12..f2ae61e0 100644
--- a/include/nana/detail/linux_X11/platform_spec.hpp
+++ b/include/nana/detail/linux_X11/platform_spec.hpp
@@ -70,7 +70,7 @@ namespace detail
 
 	struct font_tag
 	{
-		nana::string name;
+		std::string name;
 		unsigned height;
 		unsigned weight;
 		bool italic;
diff --git a/include/nana/gui/widgets/skeletons/text_editor.hpp b/include/nana/gui/widgets/skeletons/text_editor.hpp
index cf1f207a..8cd2fb93 100644
--- a/include/nana/gui/widgets/skeletons/text_editor.hpp
+++ b/include/nana/gui/widgets/skeletons/text_editor.hpp
@@ -131,7 +131,7 @@ namespace nana{	namespace widgets
 			struct keywords;
 			class keyword_parser;
 		public:
-			using char_type = ::nana::char_t;
+			using char_type = wchar_t;
 			using size_type = textbase<char_type>::size_type;
 			using string_type = textbase<char_type>::string_type;
 
@@ -152,10 +152,10 @@ namespace nana{	namespace widgets
 			text_editor(window, graph_reference, const text_editor_scheme*);
 			~text_editor();
 
-			void set_highlight(const std::string& name, const ::nana::color&, const ::nana::color&);
-			void erase_highlight(const std::string& name);
-			void set_keyword(const ::nana::string& kw, const std::string& name, bool case_sensitive, bool whole_word_matched);
-			void erase_keyword(const ::nana::string& kw);
+			void set_highlight(const ::std::string& name, const ::nana::color&, const ::nana::color&);
+			void erase_highlight(const ::std::string& name);
+			void set_keyword(const ::std::wstring& kw, const std::string& name, bool case_sensitive, bool whole_word_matched);
+			void erase_keyword(const ::std::wstring& kw);
 
 			void set_accept(std::function<bool(char_type)>);
 			void set_accept(accepts);
@@ -164,7 +164,7 @@ namespace nana{	namespace widgets
 
 			void typeface_changed();
 
-			void indent(bool, std::function<nana::string()> generator);
+			void indent(bool, std::function<std::string()> generator);
 			void set_event(event_interface*);
 
 			/// Determine whether the text_editor is line wrapped.
@@ -174,7 +174,7 @@ namespace nana{	namespace widgets
 
 			void border_renderer(std::function<void(graph_reference, const ::nana::color& bgcolor)>);
 
-			bool load(const nana::char_t*);
+			bool load(const char*);
 
 			/// Sets the text area.
 			/// @return true if the area is changed with the new value.
@@ -183,7 +183,7 @@ namespace nana{	namespace widgets
 			/// Returns the text area
 			rectangle text_area(bool including_scroll) const;
 
-			bool tip_string(nana::string&&);
+			bool tip_string(::std::string&&);
 
 			const attributes & attr() const;
 			bool multi_lines(bool);
@@ -201,9 +201,9 @@ namespace nana{	namespace widgets
 			unsigned line_height() const;
 			unsigned screen_lines() const;
 
-			bool getline(std::size_t pos, nana::string&) const;
-			void text(nana::string);
-			nana::string text() const;
+			bool getline(std::size_t pos, ::std::wstring&) const;
+			void text(std::wstring);
+			std::wstring text() const;
 
 			/// Sets caret position through text coordinate.
 			void move_caret(const upoint&);
@@ -233,8 +233,8 @@ namespace nana{	namespace widgets
 			void draw_corner();
 			void render(bool focused);
 		public:
-			void put(nana::string);
-			void put(nana::char_t);
+			void put(std::wstring);
+			void put(wchar_t);
 			void copy() const;
 			void cut();
 			void paste();
@@ -264,11 +264,11 @@ namespace nana{	namespace widgets
 			::nana::size _m_text_area() const;
 			void _m_get_scrollbar_size();
 			void _m_reset();
-			::nana::upoint _m_put(nana::string);
+			::nana::upoint _m_put(::std::wstring);
 			::nana::upoint _m_erase_select();
 
-			bool _m_make_select_string(nana::string&) const;
-			static bool _m_resolve_text(const nana::string&, std::vector<std::pair<std::size_t, std::size_t>> & lines);
+			bool _m_make_select_string(::std::wstring&) const;
+			static bool _m_resolve_text(const ::std::wstring&, std::vector<std::pair<std::size_t, std::size_t>> & lines);
 
 			bool _m_cancel_select(int align);
 			unsigned _m_tabs_pixels(size_type tabs) const;
@@ -283,10 +283,10 @@ namespace nana{	namespace widgets
 			/// Returns the right/bottom point of text area.
 			int _m_end_pos(bool right) const;	
 
-			void _m_draw_parse_string(const keyword_parser&, bool rtl, ::nana::point pos, const ::nana::color& fgcolor, const ::nana::char_t*, std::size_t len) const;
+			void _m_draw_parse_string(const keyword_parser&, bool rtl, ::nana::point pos, const ::nana::color& fgcolor, const wchar_t*, std::size_t len) const;
 			//_m_draw_string
 			//@brief: Draw a line of string
-			void _m_draw_string(int top, const ::nana::color&, const nana::upoint& str_pos, const nana::string&, bool if_mask) const;
+			void _m_draw_string(int top, const ::nana::color&, const nana::upoint& str_pos, const ::std::wstring&, bool if_mask) const;
 			//_m_update_caret_line
 			//@brief: redraw whole line specified by caret pos. 
 			//@return: true if caret overs the border
@@ -295,8 +295,8 @@ namespace nana{	namespace widgets
 
 			void _m_offset_y(int y);
 
-			unsigned _m_char_by_pixels(const nana::char_t*, std::size_t len, unsigned* pxbuf, int str_px, int pixels, bool is_rtl);
-			unsigned _m_pixels_by_char(const nana::string&, std::size_t pos) const;
+			unsigned _m_char_by_pixels(const wchar_t*, std::size_t len, unsigned* pxbuf, int str_px, int pixels, bool is_rtl);
+			unsigned _m_pixels_by_char(const ::std::wstring&, std::size_t pos) const;
 			void _handle_move_key(const arg_keyboard& arg);
 
 		private:
@@ -308,8 +308,8 @@ namespace nana{	namespace widgets
 			event_interface *			event_handler_{ nullptr };
 			std::unique_ptr<keywords> keywords_;
 
-			skeletons::textbase<nana::char_t> textbase_;
-			nana::char_t mask_char_{0};
+			skeletons::textbase<wchar_t> textbase_;
+			wchar_t mask_char_{0};
 
 			mutable ext_renderer_tag ext_renderer_;
 
@@ -318,7 +318,7 @@ namespace nana{	namespace widgets
 			struct indent_rep
 			{
 				bool enabled{ false };
-				std::function<nana::string()> generator;
+				std::function<std::string()> generator;
 			}indent_;
 
 			struct attributes
@@ -326,7 +326,7 @@ namespace nana{	namespace widgets
 				accepts acceptive{ accepts::no_restrict };
 				std::function<bool(char_type)> pred_acceptive;
 
-				nana::string tip_string;
+				::std::string tip_string;
 
 				bool line_wrapped{false};
 				bool multi_lines{true};
diff --git a/include/nana/gui/widgets/skeletons/textbase.hpp b/include/nana/gui/widgets/skeletons/textbase.hpp
index 32527879..975025e1 100644
--- a/include/nana/gui/widgets/skeletons/textbase.hpp
+++ b/include/nana/gui/widgets/skeletons/textbase.hpp
@@ -57,13 +57,12 @@ namespace skeletons
 					((text_cont_.size() == 1) && (text_cont_[0].empty())));
 		}
 
-		bool load(const nana::char_t* fs)
+		bool load(const char* file_utf8)
 		{
-			if (nullptr == fs)
+			if (!file_utf8)
 				return false;
 
-			std::string fs_mbs = nana::charset(fs);
-			std::ifstream ifs(fs_mbs.data());
+			std::ifstream ifs(to_osmbstr(file_utf8));
 			if (!ifs)
 				return false;
 
@@ -81,7 +80,7 @@ namespace skeletons
 					if(0xBB == ch && 0xBF == ifs.get())
 					{
 						ifs.close();
-						return load(fs, nana::unicode::utf8);
+						return load(file_utf8, nana::unicode::utf8);
 					}
 				}
 				else if(0xFF == ch)
@@ -94,11 +93,11 @@ namespace skeletons
 							if(ifs.get() == 0 && ifs.get() == 0)
 							{
 								ifs.close();
-								return load(fs, nana::unicode::utf32);
+								return load(file_utf8, nana::unicode::utf32);
 							}
 						}
 						ifs.close();
-						return load(fs, nana::unicode::utf16);
+						return load(file_utf8, nana::unicode::utf16);
 					}
 				}
 				else if(0xFE == ch)
@@ -107,7 +106,7 @@ namespace skeletons
 					{
 						//UTF16(big-endian)
 						ifs.close();
-						return load(fs, nana::unicode::utf16);
+						return load(file_utf8, nana::unicode::utf16);
 					}
 				}
 				else if(0 == ch)
@@ -119,7 +118,7 @@ namespace skeletons
 						{
 							//UTF32(big_endian)
 							ifs.close();
-							return load(fs, nana::unicode::utf32);
+							return load(file_utf8, nana::unicode::utf32);
 						}
 					}
 				}
@@ -143,7 +142,7 @@ namespace skeletons
 				}
 			}
 
-			_m_saved(fs);
+			_m_saved(file_utf8);
 			return true;
 		}
 
@@ -175,13 +174,12 @@ namespace skeletons
 			}
 		}
 
-		bool load(const nana::char_t * fs, nana::unicode encoding)
+		bool load(const char* file_utf8, nana::unicode encoding)
 		{
-			if (nullptr == fs)
+			if (!file_utf8)
 				return false;
 
-			std::string fs_mbs = nana::charset(fs);
-			std::ifstream ifs(fs_mbs.data());
+			std::ifstream ifs(to_osmbstr(file_utf8));
 
 			if (!ifs)
 				return false;
@@ -245,14 +243,13 @@ namespace skeletons
 				}
 			}
 
-			_m_saved(fs);
+			_m_saved(file_utf8);
 			return true;
 		}
 
-		void store(nana::string fs, bool is_unicode, ::nana::unicode encoding) const
+		void store(std::string fs, bool is_unicode, ::nana::unicode encoding) const
 		{
-			std::string fs_mbs = nana::charset(fs);
-			std::ofstream ofs(fs_mbs.data(), std::ios::binary);
+			std::ofstream ofs(to_osmbstr(fs), std::ios::binary);
 			if(ofs && text_cont_.size())
 			{
 				std::string last_mbs;
@@ -410,7 +407,7 @@ namespace skeletons
 		{
 			std::deque<string_type>().swap(text_cont_);
 			attr_max_.reset();
-			_m_saved(nana::string());
+			_m_saved(std::string());
 		}
 
 		void merge(size_type pos)
@@ -427,7 +424,7 @@ namespace skeletons
 			}
 		}
 
-		const nana::string& filename() const
+		const std::string& filename() const
 		{
 			return filename_;
 		}
@@ -489,7 +486,7 @@ namespace skeletons
 				evt_agent_->first_change();
 		}
 
-		void _m_saved(nana::string && filename) const
+		void _m_saved(std::string && filename) const
 		{
 			if(filename_ != filename)
 			{
@@ -518,7 +515,7 @@ namespace skeletons
 		textbase_event_agent_interface* evt_agent_{ nullptr };
 
 		mutable bool			changed_{ false };
-		mutable nana::string	filename_;	//A string for the saved filename.
+		mutable std::string	filename_;	//A string for the saved filename.
 		const string_type nullstr_;
 
 		struct attr_max
diff --git a/include/nana/gui/widgets/spinbox.hpp b/include/nana/gui/widgets/spinbox.hpp
index 4bc85000..e3d28505 100644
--- a/include/nana/gui/widgets/spinbox.hpp
+++ b/include/nana/gui/widgets/spinbox.hpp
@@ -97,14 +97,14 @@ namespace nana
 		void range(std::initializer_list<std::wstring> values);
 
 		/// Gets the spined value
-		::nana::string value() const;
-		void value(const ::nana::string&);
+		::std::string value() const;
+		void value(const ::std::string&);
 		int to_int() const;
 		double to_double() const;
 
 		/// Sets the modifiers
-		void modifier(std::wstring prefix, std::wstring suffix);
-		void modifier(const std::string & prefix_utf8, const std::string& suffix_utf8);
+		void modifier(std::string prefix_utf8, std::string suffix_utf8);
+		void modifier(const std::wstring & prefix, const std::wstring& suffix);
 	private:
 		native_string_type _m_caption() const throw();
 		void _m_caption(native_string_type&&);
diff --git a/include/nana/gui/widgets/textbox.hpp b/include/nana/gui/widgets/textbox.hpp
index 65c37522..5ebf27ed 100644
--- a/include/nana/gui/widgets/textbox.hpp
+++ b/include/nana/gui/widgets/textbox.hpp
@@ -126,19 +126,19 @@ namespace nana
 		textbox(window, const rectangle& = rectangle(), bool visible = true);
 
         ///  \brief Loads a text file. When attempt to load a unicode encoded text file, be sure the file have a BOM header.
-		void load(nana::string file);
-		void store(nana::string file);
-		void store(nana::string file, nana::unicode encoding);
+		void load(std::string file);
+		void store(std::string file);
+		void store(std::string file, nana::unicode encoding);
 
 		/// Enables/disables the textbox to indent a line. Idents a new line when it is created by pressing enter.
 		/// @param generator generates text for identing a line. If it is empty, textbox indents the line according to last line.
-		textbox& indention(bool, std::function<nana::string()> generator = {});
+		textbox& indention(bool, std::function<std::string()> generator = {});
 
 		//A workaround for reset, explicit default constructor syntax, because VC2013 incorrectly treats {} as {0}.
-		textbox& reset(nana::string = nana::string());      ///< discard the old text and set a new text
+		textbox& reset(const std::string& = std::string());      ///< discard the old text and set a new text
 
 		/// The file of last store operation.
-		nana::string filename() const;
+		std::string filename() const;
 
 		/// Determine whether the text was edited.
 		bool edited() const;
@@ -150,7 +150,7 @@ namespace nana
 		bool saved() const;
 
         /// Read the text from a specified line. It returns true for success.
-		bool getline(std::size_t pos, nana::string&) const;
+		bool getline(std::size_t pos, std::string&) const;
 
 		/// Gets the caret position
 		/// Returns true if the caret is in the area of display, false otherwise.
@@ -160,7 +160,7 @@ namespace nana
 		textbox& caret_pos(const upoint&);
 
         /// Appends an string. If `at_caret` is `true`, the string is inserted at the position of caret, otherwise, it is appended at end of the textbox.
-		textbox& append(const nana::string& text, bool at_caret);
+		textbox& append(const std::string& text, bool at_caret);
 
 		/// Determine wheter the text is line wrapped.
 		bool line_wrapped() const;
@@ -197,7 +197,7 @@ namespace nana
 		void erase_highlight(const std::string& name);
 		void set_keywords(const std::string& name, bool case_sensitive, bool whole_word_match, std::initializer_list<std::wstring> kw_list);
 		void set_keywords(const std::string& name, bool case_sensitive, bool whole_word_match, std::initializer_list<std::string> kw_list_utf8);
-		void erase_keyword(const nana::string& kw);
+		void erase_keyword(const std::string& kw);
 
 		/// Returns the text position of each line that currently displays on screen.
 		text_positions text_position() const;
diff --git a/source/filesystem/fs_utility.cpp b/source/filesystem/fs_utility.cpp
index 19b5f408..fc8b5992 100644
--- a/source/filesystem/fs_utility.cpp
+++ b/source/filesystem/fs_utility.cpp
@@ -50,6 +50,7 @@ namespace filesystem
 	typedef nana::string string_t;
 	const nana::char_t* splstr = L"/\\";
 #endif
+
 	//class path
 		path::path(){}
 
@@ -122,6 +123,7 @@ namespace filesystem
 		}
 	//end class path
 
+
 	namespace detail
 	{
 		//rm_dir_recursive
diff --git a/source/gui/msgbox.cpp b/source/gui/msgbox.cpp
index adaffb22..b25efe40 100644
--- a/source/gui/msgbox.cpp
+++ b/source/gui/msgbox.cpp
@@ -708,7 +708,7 @@ namespace nana
 		impl->spinbox.create(impl->dock, rectangle{ static_cast<int>(label_px + 10), 0, value_px, 0 });
 		impl->spinbox.range(impl->begin, impl->last, impl->step);
 
-		impl->spinbox.value(std::to_wstring(impl->value));
+		impl->spinbox.value(std::to_string(impl->value));
 
 		impl->dock.events().resized.connect_unignorable([impl, label_px, value_px](const ::nana::arg_resized& arg)
 		{
@@ -786,7 +786,7 @@ namespace nana
 		impl->spinbox.create(impl->dock, rectangle{ static_cast<int>(label_px + 10), 0, value_px, 0 });
 		impl->spinbox.range(impl->begin, impl->last, impl->step);
 
-		impl->spinbox.value(std::to_wstring(impl->value));
+		impl->spinbox.value(std::to_string(impl->value));
 
 		impl->dock.events().resized.connect_unignorable([impl, label_px, value_px](const ::nana::arg_resized& arg)
 		{
@@ -1017,8 +1017,8 @@ namespace nana
 
 		impl->wdg_month.option(today.month - 1);
 
-		impl->wdg_day.value(std::to_wstring(today.day));
-		impl->wdg_year.value(std::to_wstring(today.year));
+		impl->wdg_day.value(std::to_string(today.day));
+		impl->wdg_year.value(std::to_string(today.year));
 
 		impl->dock.events().resized.connect_unignorable([impl, label_px](const ::nana::arg_resized& arg)
 		{
@@ -1059,7 +1059,7 @@ namespace nana
 			if (day > days)
 				day = days;
 
-			impl->wdg_day.value(std::to_wstring(day));
+			impl->wdg_day.value(std::to_string(day));
 		};
 
 		impl->wdg_year.events().text_changed.connect_unignorable(make_days);
diff --git a/source/gui/widgets/skeletons/text_editor.cpp b/source/gui/widgets/skeletons/text_editor.cpp
index 28849477..b84c515e 100644
--- a/source/gui/widgets/skeletons/text_editor.cpp
+++ b/source/gui/widgets/skeletons/text_editor.cpp
@@ -61,7 +61,7 @@ namespace nana{	namespace widgets
 			text_editor & editor_;
 			upoint			pos_;
 			upoint			sel_a_, sel_b_;
-			nana::string	selected_text_;
+			std::wstring	selected_text_;
 		private:
 			const EnumCommand cmd_;
 		};
@@ -75,7 +75,7 @@ namespace nana{	namespace widgets
 			{
 			}
 
-			void set_removed(nana::string str)
+			void set_removed(std::wstring str)
 			{
 				//use selected_text_ as removed text
 				selected_text_ = str;
@@ -136,7 +136,7 @@ namespace nana{	namespace widgets
 			: public basic_undoable <command>
 		{
 		public:
-			undo_input_text(text_editor & editor, const nana::string& text)
+			undo_input_text(text_editor & editor, const std::wstring& text)
 				:	basic_undoable<command>(editor, command::input_text),
 					text_(text)
 			{
@@ -199,7 +199,7 @@ namespace nana{	namespace widgets
 				editor_.move_caret(editor_.points_.caret);
 			}
 		private:
-			nana::string text_;
+			std::wstring text_;
 		};
 
 		class text_editor::undo_move_text
@@ -325,9 +325,9 @@ namespace nana{	namespace widgets
 				if (pos.y > static_cast<unsigned>(textbase.lines()))
 					pos.y = static_cast<unsigned>(textbase.lines());
 
-				std::unique_ptr<nana::string> mask_str;
+				std::unique_ptr<std::wstring> mask_str;
 				if (editor_.mask_char_)
-					mask_str.reset(new nana::string(textbase.getline(pos.y).size(), editor_.mask_char_));
+					mask_str.reset(new std::wstring(textbase.getline(pos.y).size(), editor_.mask_char_));
 				
 				auto & lnstr = editor_.mask_char_ ? *mask_str : textbase.getline(pos.y);
 
@@ -345,9 +345,9 @@ namespace nana{	namespace widgets
 				//Convert the screen point to text caret point
 				const string_type& real_str = editor_.textbase_.getline(res.y);
 
-				std::unique_ptr<nana::string> mask_str;
+				std::unique_ptr<std::wstring> mask_str;
 				if (editor_.mask_char_)
-					mask_str.reset(new nana::string(real_str.size(), editor_.mask_char_));
+					mask_str.reset(new std::wstring(real_str.size(), editor_.mask_char_));
 				
 				auto & lnstr = (editor_.mask_char_ ? *mask_str : real_str);
 				if (lnstr.size() > 0)
@@ -539,8 +539,8 @@ namespace nana{	namespace widgets
 				std::size_t line = 0;
 				for (auto & mtr: linemtr_)
 				{
-					const nana::string& linestr = editor_.textbase_.getline(line);
-					const nana::char_t * p = mtr.line_sections.front().begin;
+					auto& linestr = editor_.textbase_.getline(line);
+					auto p = mtr.line_sections.front().begin;
 					if (p < linestr.data() || (linestr.data() + linestr.size() < p))
 						pre_calc_line(line, editor_.width_pixels());
 
@@ -562,8 +562,8 @@ namespace nana{	namespace widgets
 					{
 						if (line < pos || (pos + lines) <= line)
 						{
-							const nana::string& linestr = editor_.textbase_.getline(line);
-							const nana::char_t * p = mtr.line_sections.front().begin;
+							auto & linestr = editor_.textbase_.getline(line);
+							auto p = mtr.line_sections.front().begin;
 							if (p < linestr.data() || (linestr.data() + linestr.size() < p))
 								pre_calc_line(line, editor_.width_pixels());
 						}
@@ -697,7 +697,7 @@ namespace nana{	namespace widgets
 					for (std::size_t pos = 0; pos < secondary_before; ++pos, top+=pixels)
 					{
 						auto & sct = linemtr_[textline].line_sections[pos];
-						editor_._m_draw_string(top, fgcolor, nana::upoint(static_cast<unsigned>(sct.begin - text_ptr), editor_.points_.caret.y), nana::string(sct.begin, sct.end), true);
+						editor_._m_draw_string(top, fgcolor, nana::upoint(static_cast<unsigned>(sct.begin - text_ptr), editor_.points_.caret.y), std::wstring(sct.begin, sct.end), true);
 					}
 				}
 				else
@@ -727,7 +727,7 @@ namespace nana{	namespace widgets
 						auto & mtr = linemtr_[primary];
 						auto & section = mtr.line_sections[secondary];
 
-						nana::string text(section.begin, section.end);
+						std::wstring text(section.begin, section.end);
 						editor_._m_draw_string(top, fgcolor, str_pos, text, true);
 						line_index.push_back(str_pos);
 						++secondary;
@@ -767,7 +767,7 @@ namespace nana{	namespace widgets
 				nana::point scrpos;
 				if (0 != pos.x)
 				{
-					nana::string str;
+					std::wstring str;
 					for (auto & sec : mtr.line_sections)
 					{
 						std::size_t chsize = sec.end - sec.begin;
@@ -812,9 +812,9 @@ namespace nana{	namespace widgets
 				//First of all, find the text of secondary.
 				auto real_str = mtr.line_sections[secondary];
 
-				std::unique_ptr<nana::string> mask_str;
+				std::unique_ptr<std::wstring> mask_str;
 				if (editor_.mask_char_)
-					mask_str.reset(new nana::string(real_str.end - real_str.begin, editor_.mask_char_));
+					mask_str.reset(new std::wstring(real_str.end - real_str.begin, editor_.mask_char_));
 
 				const ::nana::char_t * str = (editor_.mask_char_ ? mask_str->data() : real_str.begin);
 
@@ -925,7 +925,7 @@ namespace nana{	namespace widgets
 				return true;
 			}
 		private:
-			void _m_text_section(const nana::string& str, std::vector<text_section>& tsec)
+			void _m_text_section(const std::wstring& str, std::vector<text_section>& tsec)
 			{
 				if (str.empty())
 				{
@@ -1148,12 +1148,12 @@ namespace nana{	namespace widgets
 
 		struct keyword_desc
 		{
-			::nana::string text;
+			std::wstring text;
 			std::string scheme;
 			bool case_sensitive;
 			bool whole_word_matched;
 
-			keyword_desc(const ::nana::string& txt, const std::string& schm, bool cs, bool wwm)
+			keyword_desc(const std::wstring& txt, const std::string& schm, bool cs, bool wwm)
 				: text(txt), scheme(schm), case_sensitive(cs), whole_word_matched(wwm)
 			{}
 		};
@@ -1174,12 +1174,12 @@ namespace nana{	namespace widgets
 		class text_editor::keyword_parser
 		{
 		public:
-			void parse(const ::nana::string& text, const keywords* kwptr)
+			void parse(const std::wstring& text, const keywords* kwptr)
 			{
 				if ( kwptr->kwbase.empty() || text.empty() )
 					return;
 
-                using index = ::nana::string::size_type;
+                using index = std::wstring::size_type;
 
 				std::vector<entity> entities;
 
@@ -1329,7 +1329,7 @@ namespace nana{	namespace widgets
 			keywords_->schemes.erase(name);
 		}
 
-		void text_editor::set_keyword(const ::nana::string& kw, const std::string& name, bool case_sensitive, bool whole_word_matched)
+		void text_editor::set_keyword(const ::std::wstring& kw, const std::string& name, bool case_sensitive, bool whole_word_matched)
 		{
 			for (auto & ds : keywords_->kwbase)
 			{
@@ -1344,7 +1344,7 @@ namespace nana{	namespace widgets
 			keywords_->kwbase.emplace_back(kw, name, case_sensitive, whole_word_matched);
 		}
 
-		void text_editor::erase_keyword(const ::nana::string& kw)
+		void text_editor::erase_keyword(const ::std::wstring& kw)
 		{
 			for (auto i = keywords_->kwbase.begin(); i != keywords_->kwbase.end(); ++i)
 				if (i->text == kw)
@@ -1446,7 +1446,7 @@ namespace nana{	namespace widgets
 			behavior_->pre_calc_lines(width_pixels());
 		}
 
-		void text_editor::indent(bool enb, std::function<nana::string()> generator)
+		void text_editor::indent(bool enb, std::function<std::string()> generator)
 		{
 			indent_.enabled = enb;
 			indent_.generator.swap(generator);
@@ -1493,7 +1493,7 @@ namespace nana{	namespace widgets
 			text_area_.border_renderer = f;
 		}
 
-		bool text_editor::load(const nana::char_t* fs)
+		bool text_editor::load(const char* fs)
 		{
 			if (!textbase_.load(fs))
 				return false;
@@ -1533,7 +1533,7 @@ namespace nana{	namespace widgets
 			return r;
 		}
 
-		bool text_editor::tip_string(nana::string&& str)
+		bool text_editor::tip_string(::std::string&& str)
 		{
 			if(attributes_.tip_string == str)
 				return false;
@@ -1739,7 +1739,7 @@ namespace nana{	namespace widgets
 			return textbase_;
 		}
 
-		bool text_editor::getline(std::size_t pos, nana::string& text) const
+		bool text_editor::getline(std::size_t pos, std::wstring& text) const
 		{
 			if (textbase_.lines() <= pos)
 				return false;
@@ -1748,16 +1748,16 @@ namespace nana{	namespace widgets
 			return true;
 		}
 
-		void text_editor::text(nana::string str)
+		void text_editor::text(std::wstring str)
 		{
 			textbase_.erase_all();
 			_m_reset();
 			put(std::move(str));
 		}
 
-		nana::string text_editor::text() const
+		std::wstring text_editor::text() const
 		{
-			nana::string str;
+			std::wstring str;
 			std::size_t lines = textbase_.lines();
 			if(lines > 0)
 			{
@@ -1984,7 +1984,7 @@ namespace nana{	namespace widgets
 			text_area_.border_renderer(graph_, bgcolor);
 		}
 	//public:
-		void text_editor::put(nana::string text)
+		void text_editor::put(std::wstring text)
 		{
 			auto undo_ptr = std::unique_ptr<undo_input_text>{ new undo_input_text(*this, text) };
 
@@ -2010,9 +2010,11 @@ namespace nana{	namespace widgets
 			}
 		}
 
-		void text_editor::put(nana::char_t c)
+		void text_editor::put(wchar_t ch)
 		{
-			auto undo_ptr = std::unique_ptr < undo_input_text > {new undo_input_text(*this, nana::string(1, c))};
+			std::wstring ch_str(1, ch);
+
+			auto undo_ptr = std::unique_ptr < undo_input_text > {new undo_input_text(*this, ch_str)};
 			bool refresh = (select_.a != select_.b);
 
 			undo_ptr->set_selected_text();
@@ -2023,7 +2025,7 @@ namespace nana{	namespace widgets
 			undo_.push(std::move(undo_ptr));
 
 			auto secondary_before = behavior_->take_lines(points_.caret.y);
-			textbase_.insert(points_.caret, nana::string(1, c));
+			textbase_.insert(points_.caret, std::move(ch_str));
 			behavior_->pre_calc_line(points_.caret.y, width_pixels());
 			points_.caret.x ++;
 
@@ -2039,7 +2041,7 @@ namespace nana{	namespace widgets
 
 		void text_editor::copy() const
 		{
-			nana::string str;
+			std::wstring str;
 			if(_m_make_select_string(str))
 				nana::system::dataexch().set(str);
 		}
@@ -2052,7 +2054,7 @@ namespace nana{	namespace widgets
 
 		void text_editor::paste()
 		{
-			nana::string text;
+			std::wstring text;
 			nana::system::dataexch().get(text);
 
 			//If it is required check the acceptable
@@ -2077,7 +2079,7 @@ namespace nana{	namespace widgets
 			if(false == attributes_.multi_lines)
 				return;
 
-			auto undo_ptr = std::unique_ptr<undo_input_text>(new undo_input_text(*this, nana::string(1, '\n')));
+			auto undo_ptr = std::unique_ptr<undo_input_text>(new undo_input_text(*this, std::wstring(1, '\n')));
 			bool need_refresh = (select_.a != select_.b);
 
 			undo_ptr->set_selected_text();
@@ -2098,8 +2100,8 @@ namespace nana{	namespace widgets
 			else
 			{
 				if (textbase_.lines() == 0)
-					textbase_.insertln(0, nana::string{});
-				textbase_.insertln(points_.caret.y, nana::string{});
+					textbase_.insertln(0, std::wstring{});
+				textbase_.insertln(points_.caret.y, std::wstring{});
 			}
 
 			if (record_undo)
@@ -2120,10 +2122,10 @@ namespace nana{	namespace widgets
 
 			if (indent_.enabled)
 			{
-				nana::string indent_text;
+				std::wstring indent_text;
 				if (indent_.generator)
 				{
-					indent_text = indent_.generator();
+					indent_text = to_wstring(indent_.generator());
 				}
 				else
 				{
@@ -2203,7 +2205,7 @@ namespace nana{	namespace widgets
 					textbase_.merge(points_.caret.y);
 					behavior_->merge_lines(points_.caret.y, points_.caret.y + 1);
 					undo_ptr->set_caret_pos();
-					undo_ptr->set_removed(nana::string(1, '\n'));
+					undo_ptr->set_removed(std::wstring(1, '\n'));
 				}
 				else
 					undo_ptr.reset();
@@ -2658,13 +2660,13 @@ namespace nana{	namespace widgets
 			select_.a = select_.b;
 		}
 
-		nana::upoint text_editor::_m_put(nana::string text)
+		nana::upoint text_editor::_m_put(std::wstring text)
 		{
 			auto crtpos = points_.caret;
 			std::vector<std::pair<std::size_t, std::size_t>> lines;
 			if (_m_resolve_text(text, lines) && attributes_.multi_lines)
 			{
-				nana::string str_orig = textbase_.getline(crtpos.y);
+				auto str_orig = textbase_.getline(crtpos.y);
 				auto x_orig = crtpos.x;
 
 				auto subpos = lines.front();
@@ -2713,7 +2715,7 @@ namespace nana{	namespace widgets
 			{
 				if(a.y != b.y)
 				{
-					textbase_.erase(a.y, a.x, nana::string::npos);
+					textbase_.erase(a.y, a.x, std::wstring::npos);
 					textbase_.erase(a.y + 1, b.y - a.y - 1);
 
 					textbase_.erase(a.y + 1, 0, b.x);
@@ -2734,7 +2736,7 @@ namespace nana{	namespace widgets
 			return points_.caret;
 		}
 
-		bool text_editor::_m_make_select_string(nana::string& text) const
+		bool text_editor::_m_make_select_string(std::wstring& text) const
 		{
 			nana::upoint a, b;
 			if (!_m_get_sort_select_points(a, b))
@@ -2782,7 +2784,7 @@ namespace nana{	namespace widgets
 			return pos + 1;
 		}
 
-		bool text_editor::_m_resolve_text(const nana::string& text, std::vector<std::pair<std::size_t, std::size_t>> & lines)
+		bool text_editor::_m_resolve_text(const std::wstring& text, std::vector<std::pair<std::size_t, std::size_t>> & lines)
 		{
 			auto const text_str = text.data();
 			std::size_t begin = 0;
@@ -2863,7 +2865,7 @@ namespace nana{	namespace widgets
 
 			if(mask_char_)
 			{
-				nana::string maskstr;
+				std::wstring maskstr;
 				maskstr.append(n, mask_char_);
 				return graph_.text_extent_size(maskstr);
 			}
@@ -2910,7 +2912,7 @@ namespace nana{	namespace widgets
 		bool text_editor::_m_move_select(bool record_undo)
 		{
 			nana::upoint caret = points_.caret;
-			nana::string text;
+			std::wstring text;
 			if (_m_make_select_string(text))
 			{
 				auto undo_ptr = std::unique_ptr<undo_move_text>(new undo_move_text(*this));
@@ -2972,7 +2974,7 @@ namespace nana{	namespace widgets
 			return static_cast<int>(text_area_.area.y + text_area_.area.height - text_area_.hscroll);
 		}
 
-		void text_editor::_m_draw_parse_string(const keyword_parser& parser, bool rtl, ::nana::point pos, const ::nana::color& fgcolor, const ::nana::char_t* str, std::size_t len) const
+		void text_editor::_m_draw_parse_string(const keyword_parser& parser, bool rtl, ::nana::point pos, const ::nana::color& fgcolor, const wchar_t* str, std::size_t len) const
 		{
 			graph_.set_text_color(fgcolor);
 			graph_.string(pos, str, len);
@@ -3034,14 +3036,14 @@ namespace nana{	namespace widgets
 			}
 		}
 
-		void text_editor::_m_draw_string(int top, const ::nana::color& clr, const nana::upoint& str_pos, const nana::string& str, bool if_mask) const
+		void text_editor::_m_draw_string(int top, const ::nana::color& clr, const nana::upoint& str_pos, const std::wstring& str, bool if_mask) const
 		{
 			::nana::point text_pos{ text_area_.area.x - points_.offset.x, top };
 			const int text_right = text_area_.area.right();
 
-			std::unique_ptr<nana::string> mask_str;
+			std::unique_ptr<std::wstring> mask_str;
 			if (if_mask && mask_char_)
-				mask_str.reset(new nana::string(str.size(), mask_char_));
+				mask_str.reset(new std::wstring(str.size(), mask_char_));
 
 			bool focused = API::is_focus_ready(window_);
 
@@ -3322,7 +3324,7 @@ namespace nana{	namespace widgets
 			points_.offset.y = y;
 		}
 
-		unsigned text_editor::_m_char_by_pixels(const nana::char_t* str, std::size_t len, unsigned * pxbuf, int str_px, int pixels, bool is_rtl)
+		unsigned text_editor::_m_char_by_pixels(const wchar_t* str, std::size_t len, unsigned * pxbuf, int str_px, int pixels, bool is_rtl)
 		{
 			if (graph_.glyph_pixels(str, len, pxbuf))
 			{
@@ -3361,7 +3363,7 @@ namespace nana{	namespace widgets
 			return 0;
 		}
 
-		unsigned text_editor::_m_pixels_by_char(const nana::string& lnstr, std::size_t pos) const
+		unsigned text_editor::_m_pixels_by_char(const std::wstring& lnstr, std::size_t pos) const
 		{
 			if (pos > lnstr.size())
 				return 0;
diff --git a/source/gui/widgets/spinbox.cpp b/source/gui/widgets/spinbox.cpp
index f2ed5c3d..f5836f9e 100644
--- a/source/gui/widgets/spinbox.cpp
+++ b/source/gui/widgets/spinbox.cpp
@@ -25,6 +25,7 @@ namespace nana
 	{
 		namespace spinbox
 		{
+
 			class event_agent
 				: public widgets::skeletons::textbase_event_agent_interface
 			{
@@ -53,13 +54,13 @@ namespace nana
 			public:
 				virtual ~range_interface() = default;
 
-				virtual std::wstring value() const = 0;
+				virtual std::string value() const = 0;
 
 				//sets a new value, the diff indicates whether the new value is different from the current value.
 				//returns true if the new value is acceptable.
-				virtual bool value(const std::wstring& new_value, bool& diff) = 0;
+				virtual bool value(const std::string& new_value, bool& diff) = 0;
 
-				virtual bool check_value(const std::wstring&) const = 0;
+				virtual bool check_value(const std::string&) const = 0;
 				virtual void spin(bool increase) = 0;
 			};
 
@@ -72,14 +73,14 @@ namespace nana
 					: begin_{ vbegin }, last_{ vlast }, step_{ step }, value_{ vbegin }
 				{}
 
-				std::wstring value() const override
+				std::string value() const override
 				{
-					return std::to_wstring(value_);
+					return std::to_string(value_);
 				}
 
-				bool value(const std::wstring& value_str, bool & diff) override
+				bool value(const std::string& value_str, bool & diff) override
 				{
-					std::wstringstream ss;
+					std::stringstream ss;
 					ss << value_str;
 
 					T v;
@@ -92,7 +93,7 @@ namespace nana
 					return true;
 				}
 
-				bool check_value(const std::wstring& str) const override
+				bool check_value(const std::string& str) const override
 				{
 					if (str.empty())
 						return true;
@@ -157,6 +158,7 @@ namespace nana
 			{
 			public:
 				range_text(std::initializer_list<std::string> & initlist)
+					: texts_(initlist)
 				{
 					for (auto & s : initlist)
 					{
@@ -165,10 +167,12 @@ namespace nana
 				}
 
 				range_text(std::initializer_list<std::wstring>& initlist)
-					: texts_(initlist)
-				{}
+				{
+					for (auto & s : initlist)
+						texts_.emplace_back(to_utf8(s));
+				}
 
-				std::wstring value() const override
+				std::string value() const override
 				{
 					if (texts_.empty())
 						return{};
@@ -176,7 +180,7 @@ namespace nana
 					return texts_[pos_];
 				}
 
-				bool value(const std::wstring& value_str, bool & diff) override
+				bool value(const std::string& value_str, bool & diff) override
 				{
 					auto i = std::find(texts_.cbegin(), texts_.cend(), value_str);
 					if (i != texts_.cend())
@@ -188,7 +192,7 @@ namespace nana
 					return false;
 				}
 
-				bool check_value(const std::wstring& str) const override
+				bool check_value(const std::string& str) const override
 				{
 					if (str.empty())
 						return true;
@@ -219,7 +223,7 @@ namespace nana
 					}
 				}
 			private:
-				std::vector<std::wstring> texts_;
+				std::vector<std::string> texts_;
 				std::size_t pos_{0};
 			};
 
@@ -262,7 +266,7 @@ namespace nana
 						else
 							str.insert(pos, 1, ch);
 
-						return range_->check_value(str);
+						return range_->check_value(to_utf8(str));
 					});
 
 					evt_agent_.reset(new event_agent(static_cast<nana::spinbox&>(wdg)));
@@ -286,12 +290,12 @@ namespace nana
 					editor_ = nullptr;
 				}
 
-				::nana::string value() const
+				std::string value() const
 				{
 					return range_->value();
 				}
 
-				bool value(const ::nana::string& value_str)
+				bool value(const ::std::string& value_str)
 				{
 					bool diff;
 					if (!range_->value(value_str, diff))
@@ -309,7 +313,7 @@ namespace nana
 					reset_text();
 				}
 
-				void modifier(std::wstring&& prefix, std::wstring&& suffix)
+				void modifier(std::string&& prefix, std::string&& suffix)
 				{
 					modifier_.prefix = std::move(prefix);
 					modifier_.suffix = std::move(suffix);
@@ -417,9 +421,9 @@ namespace nana
 						return;
 
 					if (API::is_focus_ready(editor_->window_handle()))
-						editor_->text(range_->value());
+						editor_->text(to_wstring(range_->value()));
 					else
-						editor_->text(modifier_.prefix + range_->value() + modifier_.suffix);
+						editor_->text(to_wstring(modifier_.prefix + range_->value() + modifier_.suffix));
 
 					_m_draw_spins(spin_stated_);
 				}
@@ -483,8 +487,8 @@ namespace nana
 
 				struct modifiers
 				{
-					std::wstring prefix;
-					std::wstring suffix;
+					std::string prefix;
+					std::string suffix;
 				}modifier_;
 			};
 
@@ -567,7 +571,7 @@ namespace nana
 			{
 				if (impl_->editor()->respond_char(arg))
 				{
-					if (!impl_->value(impl_->editor()->text()))
+					if (!impl_->value(to_utf8(impl_->editor()->text())))
 						impl_->draw_spins();
 
 					API::lazy_refresh();
@@ -639,7 +643,7 @@ namespace nana
 		API::refresh_window(handle());
 	}
 
-	::nana::string spinbox::value() const
+	::std::string spinbox::value() const
 	{
 		internal_scope_guard lock;
 		if (handle())
@@ -647,7 +651,7 @@ namespace nana
 		return{};
 	}
 
-	void spinbox::value(const ::nana::string& s)
+	void spinbox::value(const ::std::string& s)
 	{
 		internal_scope_guard lock;
 		if (handle())
@@ -667,14 +671,14 @@ namespace nana
 		return std::stod(value());
 	}
 
-	void spinbox::modifier(std::wstring prefix, std::wstring suffix)
+	void spinbox::modifier(std::string prefix, std::string suffix)
 	{
 		get_drawer_trigger().impl()->modifier(std::move(prefix), std::move(suffix));
 	}
 
-	void spinbox::modifier(const std::string & prefix_utf8, const std::string& suffix_utf8)
+	void spinbox::modifier(const std::wstring & prefix, const std::wstring& suffix)
 	{
-		modifier(static_cast<std::wstring>(::nana::charset(prefix_utf8, ::nana::unicode::utf8)), static_cast<std::wstring>(::nana::charset(suffix_utf8, ::nana::unicode::utf8)));
+		modifier(to_utf8(prefix), to_utf8(suffix));
 	}
 
 	auto spinbox::_m_caption() const throw() -> native_string_type
diff --git a/source/gui/widgets/textbox.cpp b/source/gui/widgets/textbox.cpp
index 71a7b794..316b36d8 100644
--- a/source/gui/widgets/textbox.cpp
+++ b/source/gui/widgets/textbox.cpp
@@ -228,7 +228,7 @@ namespace drawerbase {
 			create(wd, r, visible);
 		}
 
-		void textbox::load(nana::string file)
+		void textbox::load(std::string file)
 		{
 			internal_scope_guard lock;
 			auto editor = get_drawer_trigger().editor();
@@ -236,7 +236,7 @@ namespace drawerbase {
 				API::update_window(handle());
 		}
 
-		void textbox::store(nana::string file)
+		void textbox::store(std::string file)
 		{
 			internal_scope_guard lock;
 			auto editor = get_drawer_trigger().editor();
@@ -244,7 +244,7 @@ namespace drawerbase {
 				editor->textbase().store(std::move(file), false, nana::unicode::utf8);	//3rd parameter is just for syntax, it will be ignored
 		}
 
-		void textbox::store(nana::string file, nana::unicode encoding)
+		void textbox::store(std::string file, nana::unicode encoding)
 		{
 			internal_scope_guard lock;
 			auto editor = get_drawer_trigger().editor();
@@ -254,7 +254,7 @@ namespace drawerbase {
 
 		/// Enables/disables the textbox to indent a line. Idents a new line when it is created by pressing enter.
 		/// @param generator generates text for identing a line. If it is empty, textbox indents the line according to last line.
-		textbox& textbox::indention(bool enb, std::function<nana::string()> generator)
+		textbox& textbox::indention(bool enb, std::function<std::string()> generator)
 		{
 			internal_scope_guard lock;
 			auto editor = get_drawer_trigger().editor();
@@ -263,20 +263,20 @@ namespace drawerbase {
 			return *this;
 		}
 
-		textbox& textbox::reset(nana::string str)
+		textbox& textbox::reset(const std::string& str)
 		{
 			internal_scope_guard lock;
 			auto editor = get_drawer_trigger().editor();
 			if (editor)
 			{
-				editor->text(std::move(str));
+				editor->text(to_wstring(str));
 				editor->textbase().reset();
 				API::update_window(this->handle());
 			}
 			return *this;
 		}
 
-		nana::string textbox::filename() const
+		std::string textbox::filename() const
 		{
 			internal_scope_guard lock;
 			auto editor = get_drawer_trigger().editor();
@@ -310,11 +310,20 @@ namespace drawerbase {
 			return (editor ? editor->textbase().saved() : false);
 		}
 
-		bool textbox::getline(std::size_t line_index, nana::string& text) const
+		bool textbox::getline(std::size_t line_index, std::string& text) const
 		{
 			internal_scope_guard lock;
 			auto editor = get_drawer_trigger().editor();
-			return (editor ? editor->getline(line_index, text) : false);
+			if (editor)
+			{
+				std::wstring line_text;
+				if (editor->getline(line_index, line_text))
+				{
+					text = utf8_cast(line_text);
+					return true;
+				}
+			}
+			return false;
 		}
 
 		/// Gets the caret position
@@ -349,7 +358,7 @@ namespace drawerbase {
 			return *this;
 		}
 
-		textbox& textbox::append(const nana::string& text, bool at_caret)
+		textbox& textbox::append(const std::string& text, bool at_caret)
 		{
 			internal_scope_guard lock;
 			auto editor = get_drawer_trigger().editor();
@@ -358,7 +367,7 @@ namespace drawerbase {
 				if(at_caret == false)
 					editor->move_caret_end();
 
-				editor->put(text);
+				editor->put(to_wstring(text));
 				API::update_window(this->handle());
 			}
 			return *this;
@@ -423,10 +432,9 @@ namespace drawerbase {
 
 		textbox& textbox::tip_string(std::string str)
 		{
-			throw_not_utf8(str);
 			internal_scope_guard lock;
 			auto editor = get_drawer_trigger().editor();
-			if(editor && editor->tip_string(utf8_cast(str)))
+			if(editor && editor->tip_string(std::move(str)))
 				API::refresh_window(handle());
 			return *this;
 		}
@@ -559,12 +567,12 @@ namespace drawerbase {
 			}
 		}
 
-		void textbox::erase_keyword(const nana::string& kw)
+		void textbox::erase_keyword(const std::string& kw)
 		{
 			internal_scope_guard lock;
 			auto editor = get_drawer_trigger().editor();
 			if (editor)
-				editor->erase_keyword(kw);
+				editor->erase_keyword(to_wstring(kw));
 		}
 
 		std::vector<upoint> textbox::text_position() const