diff --git a/CMakeLists.txt b/CMakeLists.txt
index fba1b2e..665cc58 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -212,7 +212,6 @@ target_sources(system3 PRIVATE
   src/sys/ags_text.cpp
   src/sys/ags_vsp.cpp
   src/sys/ags_vsp2l.cpp
-  src/sys/ags_window.cpp
   src/sys/dri.cpp
   src/sys/game_id.cpp
   src/sys/msgskip.cpp
diff --git a/src/sys/ags.cpp b/src/sys/ags.cpp
index 8ae3c11..2a22b99 100644
--- a/src/sys/ags.cpp
+++ b/src/sys/ags.cpp
@@ -186,13 +186,10 @@ AGS::AGS(const Config& config, const GameId& game_id) : game_id(game_id)
 
 	SDL_SetPaletteColors(screen_palette, program_palette->colors, 0, 256);
 
-	init_windows();
-
 	// 画面選択
 	src_screen = dest_screen = 0;
 
 	// メッセージ表示
-	text.reset_pos(text_w[0].sx, text_w[0].sy + 2);
 	text.line_space = 2;
 	text.font_size = 16;
 	if (game_id.sys_ver == 1) {
@@ -218,7 +215,6 @@ AGS::AGS(const Config& config, const GameId& game_id) : game_id(game_id)
 		menu.frame_color = 15;
 		menu.back_color = 0;
 	}
-	menu_fix = false;
 
 	draw_hankaku = false;
 	draw_menu = false;
@@ -406,14 +402,6 @@ bool AGS::save_screenshot(const char* path)
 	return ok;
 }
 
-int AGS::calculate_menu_max(int window) {
-	if (game_id.is(GameId::INTRUDER))
-		return 6;
-	if (game_id.is(GameId::GAKUEN_SENKI))
-		return (menu_w[window - 1].ey - menu_w[window - 1].sy) / (menu.font_size + 4);
-	return 11;
-}
-
 void AGS::load_censor_list(const char* fname)
 {
 	censor_list.clear();
diff --git a/src/sys/ags.h b/src/sys/ags.h
index 6109b28..1380e58 100644
--- a/src/sys/ags.h
+++ b/src/sys/ags.h
@@ -16,39 +16,11 @@
 #include <stdio.h>
 #include "common.h"
 #include "game_id.h"
+#include "cg.h"
 #include "dri.h"
 #include <SDL_ttf.h>
 
-inline uint8_t* surface_line(SDL_Surface* surface, int y)
-{
-	return static_cast<uint8*>(surface->pixels) + surface->pitch * y;
-}
-
 struct Config;
-class FILEIO;
-
-struct SurfaceDeleter {
-	void operator()(SDL_Surface* s) const noexcept {
-		if (s) SDL_FreeSurface(s);
-	}
-};
-
-struct CG {
-	std::unique_ptr<SDL_Surface, SurfaceDeleter> surface_;
-	int x;
-	int y;
-
-	CG() = default;
-	CG(int x, int y, int width, int height)
-		: surface_(SDL_CreateRGBSurfaceWithFormat(0, width, height, 8, SDL_PIXELFORMAT_INDEX8)),
-		  x(x), y(y) {}
-	explicit operator bool() const noexcept { return static_cast<bool>(surface_); }
-
-	SDL_Surface* surface() const { return surface_.get(); }
-	int width() const { return surface_->w; }
-	int height() const { return surface_->h; }
-	SDL_Palette* palette() const { return surface_->format->palette; }
-};
 
 enum CgFlags {
 	CG_EXTRACT_CG = 1,
@@ -91,7 +63,6 @@ private:
 
 	void draw_char(int dest, int dest_x, int dest_y, uint16 code, TTF_Font* font, uint8 color);
 	void draw_char_antialias(int dest, int dest_x, int dest_y, uint16 code, TTF_Font* font, uint8 color, uint8 cache[]);
-	void draw_gaiji(int dest, int dest_x, int dest_y, const uint8_t bitmap[32], int size, uint8 color);
 
 	uint8_t palR(uint8_t col) const { return screen_palette->colors[col].r; }
 	uint8_t palG(uint8_t col) const { return screen_palette->colors[col].g; }
@@ -124,6 +95,8 @@ public:
 	uint8 get_pixel(int dest, int x, int y) const { return vram[dest][y][x]; }
 	void set_pixel(int dest, int x, int y, uint8 color) { vram[dest][y][x] = color; }
 	void invalidate_screen(int sx, int sy, int width, int height);
+	void draw_gaiji(int dest, int dest_x, int dest_y, const uint8_t bitmap[32], int size, uint8 color);
+	bool is_faded() const { return fade_level != 0; }
 
 	void fade_out(int duration_ms, bool white);
 	void fade_in(int duration_ms);
@@ -140,33 +113,11 @@ public:
 	void box_line(int dest, int sx, int sy, int ex, int ey, uint8 color);
 	void draw_window(int sx, int sy, int ex, int ey, bool frame, uint8 frame_color, uint8 back_color);
 
+	CG save_rect(int x, int y, int width, int height);
+	void restore_rect(const CG& cg);
+
 	void draw_text(std::string_view string, bool text_wait = false);
 
-	void clear_text_window(int index, bool erase);
-	bool return_text_line(int index);
-	void draw_push(int index);
-	void set_push_bitmap(const uint8_t* bitmap) { push_bitmap = bitmap; }
-	void open_text_window(int index, bool erase);
-	void close_text_window(int index, bool update);
-	void set_text_window(int index, int sx, int sy, int ex, int ey, bool save) {
-		text_w[index - 1].reset(sx, sy, ex, ey, text_w[index - 1].frame, save);
-	}
-	void set_text_window_frame(int index, bool frame) {
-		text_w[index - 1].frame = frame;
-	}
-
-	void clear_menu_window();
-	void open_menu_window(int index);
-	void redraw_menu_window(int index, int selected);
-	void close_menu_window(int index);
-	void get_menu_window_rect(int index, int* sx, int* sy, int* ex, int* ey);
-	void set_menu_window(int index, int sx, int sy, int ex, int ey, bool save) {
-		menu_w[index - 1].reset(sx, sy, ex, ey, menu_w[index - 1].frame, save);
-	}
-	void set_menu_window_frame(int index, bool frame) {
-		menu_w[index - 1].frame = frame;
-	}
-
 	void load_cursor(int page, uint8_t flags);
 	void select_cursor();
 	void translate_mouse_coords(int* x, int* y);
@@ -174,7 +125,6 @@ public:
 	bool get_scanline_mode() const { return scanline_texture; }
 	void set_scanline_mode(bool enable);
 	bool save_screenshot(const char* path);
-	int calculate_menu_max(int window);
 
 	SDL_Rect dirty_rect = {};
 
@@ -212,7 +162,6 @@ public:
 
 	// メニュー表示
 	TextContext menu;
-	bool menu_fix;
 
 	bool draw_hankaku;
 	bool draw_menu;
@@ -227,28 +176,9 @@ public:
 	uint8 cursor_color;
 	int cursor_index;
 
-	// Window (B command)
-	struct Window {
-		int sx;
-		int sy;
-		int ex;
-		int ey;
-		bool frame;
-		bool save;
-		CG screen;
-		CG window;
-
-		void reset(int sx, int sy, int ex, int ey, bool frame, bool save);
-	};
-	Window menu_w[10];
-	Window text_w[10];
-
 private:
-	void init_windows();
-
 	Dri acg;
 	const char* bmp_prefix = NULL;
-	const uint8_t* push_bitmap = nullptr;
 };
 
 extern "C" void ags_setAntialiasedStringMode(int on);
diff --git a/src/sys/ags_draw.cpp b/src/sys/ags_draw.cpp
index b8e19dd..1ca0382 100644
--- a/src/sys/ags_draw.cpp
+++ b/src/sys/ags_draw.cpp
@@ -255,3 +255,39 @@ void AGS::box_line(int dest, int sx, int sy, int ex, int ey, uint8 color)
 	}
 }
 
+void AGS::draw_window(int sx, int sy, int ex, int ey, bool frame, uint8 frame_color, uint8 back_color)
+{
+	SDL_Rect rect = {sx, sy, ex - sx + 1, ey - sy + 1};
+	SDL_FillRect(hBmpScreen[0], &rect, back_color);
+
+	if (frame) {
+		SDL_Rect rects[] = {
+			{sx + 1, sy + 1, ex - sx - 1, 2},
+			{sx + 1, ey - 2, ex - sx - 1, 2},
+			{sx + 1, sy + 1, 2, ey - sy - 1},
+			{ex - 2, sy + 1, 2, ey - sy - 1},
+		};
+		SDL_FillRects(hBmpScreen[0], rects, 4, frame_color);
+		box_line(0, sx + 4, sy + 4, ex - 4, ey - 4, frame_color);
+	}
+	invalidate_screen(sx, sy, ex - sx + 1, ey - sy + 1);
+}
+
+CG AGS::save_rect(int x, int y, int width, int height)
+{
+	CG cg(x, y, width, height);
+	SDL_SetPaletteColors(cg.palette(), screen_palette->colors, 0, 256);
+
+	SDL_Rect rect = {x, y, width, height};
+	SDL_BlitSurface(hBmpScreen[0], &rect, cg.surface(), NULL);
+	return cg;
+}
+
+void AGS::restore_rect(const CG& cg)
+{
+	SDL_SetSurfacePalette(hBmpScreen[0], cg.palette());
+	SDL_Rect rect = {cg.x, cg.y, cg.width(), cg.height()};
+	SDL_BlitSurface(cg.surface(), NULL, hBmpScreen[0], &rect);
+	invalidate_screen(cg.x, cg.y, cg.width(), cg.height());
+	SDL_SetSurfacePalette(hBmpScreen[0], screen_palette);
+}
diff --git a/src/sys/ags_window.cpp b/src/sys/ags_window.cpp
deleted file mode 100644
index a84fc85..0000000
--- a/src/sys/ags_window.cpp
+++ /dev/null
@@ -1,341 +0,0 @@
-/*
-	ALICE SOFT SYSTEM 3 for Win32
-
-	[ AGS - window ]
-*/
-
-#include "ags.h"
-#include <string.h>
-
-void AGS::Window::reset(int sx, int sy, int ex, int ey, bool frame, bool save) {
-	this->sx = sx;
-	this->sy = sy;
-	this->ex = ex;
-	this->ey = ey;
-	this->frame = frame;
-	this->save = save;
-	screen.surface_.reset();
-	window.surface_.reset();
-}
-
-void AGS::init_windows()
-{
-	for (int i = 0; i < 10; i++) {
-		// ウィンドウの初期位置はシステムによって異なる
-		switch (game_id.game) {
-		case GameId::BUNKASAI:
-			text_w[i].reset(24, 304, 616, 384, false, false);
-			menu_w[i].reset(440, 18, 620, 178, true, true);
-			break;
-		case GameId::CRESCENT:
-			text_w[i].reset(24, 288, 616, 378, false, false);
-			// 本来は横メニュー
-			menu_w[i].reset(464, 50, 623, 240, true, true);
-			break;
-		case GameId::RANCE2:
-		case GameId::RANCE2_HINT:
-			text_w[i].reset(8, 285, 502, 396, false, false);
-			menu_w[i].reset(431, 19, 624, 181, false, true);
-			break;
-		case GameId::DPS:
-		case GameId::DPS_SG_FAHREN:
-		case GameId::DPS_SG_KATEI:
-		case GameId::DPS_SG_NOBUNAGA:
-		case GameId::DPS_SG2_ANTIQUE:
-		case GameId::DPS_SG2_IKENAI:
-		case GameId::DPS_SG2_AKAI:
-		case GameId::DPS_SG3_RABBIT:
-		case GameId::DPS_SG3_SHINKON:
-		case GameId::DPS_SG3_SOTSUGYOU:
-			text_w[i].reset(48, 288, 594, 393, false, false);
-			//menu_w[i].reset(48, 288, 584, 393, false, true);
-			menu_w[i].reset(48, 288, 594, 393, false, true);
-			break;
-		case GameId::FUKEI:
-			text_w[i].reset(44, 282, 593, 396, false, false);
-			menu_w[i].reset(460, 14, 635, 214, false, true);
-			break;
-		case GameId::INTRUDER:
-			text_w[i].reset(8, 280, 629, 393, false, false);
-			menu_w[i].reset(448, 136, 623, 340, true, true);
-			break;
-		case GameId::TENGU:
-			text_w[i].reset(44, 282, 593, 396, false, false);
-			menu_w[i].reset(452, 14, 627, 214, false, true);
-			break;
-		case GameId::TOUSHIN_HINT:
-			text_w[i].reset(8, 311, 623, 391, false, false);
-			menu_w[i].reset(452, 14, 627, 214, true, true);
-			break;
-		case GameId::LITTLE_VAMPIRE:
-			text_w[i].reset(8, 255, 615, 383, false, false);
-			menu_w[i].reset(448, 11, 615, game_id.language == ENGLISH ? 234 : 224, false, true);
-			break;
-		case GameId::YAKATA:
-			text_w[i].reset(48, 288, 594, 393, false, false);
-			menu_w[i].reset(452, 14, 627, 214, false, true);
-			break;
-		case GameId::DALK_HINT:
-			text_w[i].reset(24, 308, 376, 386, false, false);
-			menu_w[i].reset(404, 28, 604, 244, true, true);
-			break;
-		case GameId::RANCE3_HINT:
-			text_w[i].reset(104, 304, 615, 383, false, false);
-			menu_w[i].reset(464, 24, 623, 200, true, true);
-			break;
-		case GameId::YAKATA2:
-			text_w[i].reset(104, 304, 620, 382, false, false);
-			menu_w[i].reset(420, 28, 620, 244, true, true);
-			break;
-		case GameId::GAKUEN_SENKI:
-			text_w[i].reset(8, 260, 505, 384, false, false);
-			if (i == 1) {
-				menu_w[i].reset(128, 32, 337, 178, true, true);
-			} else {
-				menu_w[i].reset(288, 30, 433, 210, true, true);
-			}
-			break;
-		case GameId::GAKUEN_KING:
-			switch (i) {
-			default:
-			case 0: text_w[i].reset(112, 310, 623, 391, false, false); break;
-			case 1: text_w[i].reset(48, 310, 591, 391, false, false); break;
-			case 2: text_w[i].reset(0, 0, 639, 391, false, false); break;
-			case 3: text_w[i].reset(24, 310, 183, 391, false, false); break;
-			case 4: text_w[i].reset(464, 310, 623, 391, false, false); break;
-			}
-			switch (i) {
-			default:
-			case 0: menu_w[i].reset(416, 24, 591, 248, true, true); break;
-			case 1: menu_w[i].reset(32, 16, 191, 216, true, true); break;
-			case 2: menu_w[i].reset(448, 16, 607, 216, true, true); break;
-			case 3: menu_w[i].reset(32, 223, 191, 383, true, true); break;
-			case 4: menu_w[i].reset(448, 223, 607, 383, true, true); break;
-			}
-			break;
-		default:
-			text_w[i].reset(8, 311, 623, 391, true, false);
-			menu_w[i].reset(464, 80, 623, 240, true, true);
-			break;
-		}
-	}
-}
-
-void AGS::clear_text_window(int index, bool erase)
-{
-	Window& w = text_w[index - 1];
-
-	if(erase) {
-		if (w.frame && fade_level) {
-			draw_window(w.sx - 8, w.sy - 8, w.ex + 8, w.ey + 8, true, text.frame_color, text.back_color);
-		} else {
-			box_fill(0, w.sx, w.sy, w.ex, w.ey, text.back_color);
-		}
-	}
-
-	text.reset_pos(w.sx, w.sy + 2);
-}
-
-bool AGS::return_text_line(int index)
-{
-	text.newline();
-	// Return true if the next line exceeds the bottom of the window
-	return text.pos.y + text.font_size > text_w[index - 1].ey;
-}
-
-void AGS::draw_push(int index)
-{
-	static const uint8_t builtin_bitmap[32] = {
-		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xe0, 0x00,
-		0x90, 0x00, 0x99, 0x74, 0xe9, 0x44, 0x89, 0x77,
-		0x89, 0x15, 0x87, 0x75, 0x00, 0x00, 0xff, 0xff
-	};
-
-	Window& w = text_w[index - 1];
-	int x = w.ex - 16;
-	int y = w.ey - 16;
-	draw_gaiji(0, x, y, push_bitmap ? push_bitmap : builtin_bitmap, 16, text.font_color);
-	invalidate_screen(x, y, 16, 16);
-}
-
-void AGS::open_text_window(int index, bool erase)
-{
-	Window& w = text_w[index - 1];
-	int sx = w.sx - (w.frame ? 8 : 0);
-	int sy = w.sy - (w.frame ? 8 : 0);
-	int ex = w.ex + (w.frame ? 8 : 0);
-	int ey = w.ey + (w.frame ? 8 : 0);
-	int width = ex - sx + 1;
-	int height = ey - sy + 1;
-
-	if (game_id.is(GameId::PROG_CD) && !erase) {
-		// prostudent G オープニング画面化け対策
-		w.screen = CG();
-		w.window = CG();
-	}
-
-	// 画面退避
-	if (w.save) {
-		w.screen = CG(sx, sy, width, height);
-		SDL_SetPaletteColors(w.screen.palette(), screen_palette->colors, 0, 256);
-
-		SDL_Rect rect = {sx, sy, width, height};
-		SDL_BlitSurface(hBmpScreen[0], &rect, w.screen.surface(), NULL);
-	}
-
-	if(erase) {
-		// 窓初期化
-		draw_window(sx, sy, ex, ey, w.frame, text.frame_color, text.back_color);
-	} else if (w.save && w.window) {
-		// 窓復帰
-		sx = w.window.x;
-		sy = w.window.y;
-		width = w.window.width();
-		height = w.window.height();
-
-		SDL_SetSurfacePalette(hBmpScreen[0], w.window.palette());
-		SDL_Rect rect = {sx, sy, width, height};
-		SDL_BlitSurface(w.window.surface(), NULL, hBmpScreen[0], &rect);
-		invalidate_screen(sx, sy, width, height);
-		SDL_SetSurfacePalette(hBmpScreen[0], screen_palette);
-	}
-
-	text.reset_pos(w.sx, w.sy + text.line_space);
-}
-
-void AGS::close_text_window(int index, bool update)
-{
-	Window& w = text_w[index - 1];
-	int sx = w.sx - (w.frame ? 8 : 0);
-	int sy = w.sy - (w.frame ? 8 : 0);
-	int ex = w.ex + (w.frame ? 8 : 0);
-	int ey = w.ey + (w.frame ? 8 : 0);
-	int width = ex - sx + 1;
-	int height = ey - sy + 1;
-
-	// 窓退避
-	if (w.save) {
-		w.window = CG(sx, sy, width, height);
-		SDL_SetPaletteColors(w.window.palette(), screen_palette->colors, 0, 256);
-
-		SDL_Rect rect = {sx, sy, width, height};
-		SDL_BlitSurface(hBmpScreen[0], &rect, w.window.surface(), NULL);
-	}
-
-	// 画面復帰
-	if (w.save && w.screen) {
-		sx = w.screen.x;
-		sy = w.screen.y;
-		width = w.screen.width();
-		height = w.screen.height();
-
-		SDL_SetSurfacePalette(hBmpScreen[0], w.screen.palette());
-		SDL_Rect rect = {sx, sy, width, height};
-		SDL_BlitSurface(w.screen.surface(), NULL, hBmpScreen[0], &rect);
-		invalidate_screen(sx, sy, width, height);
-		SDL_SetSurfacePalette(hBmpScreen[0], screen_palette);
-	}
-
-	if(update) {
-		text.reset_pos(w.sx, w.sy + text.line_space);
-	}
-}
-
-void AGS::clear_menu_window()
-{
-	SDL_Rect rect = {0, 0, 640, 480};
-	SDL_FillRect(hBmpScreen[2], &rect, menu.back_color);
-	menu.reset_pos(2, 2);
-}
-
-void AGS::open_menu_window(int index)
-{
-	Window &w = menu_w[index - 1];
-	int sx = w.sx;
-	int sy = w.sy;
-	int ex = w.ex;
-	int ey = menu_fix ? w.ey : sy + menu.pos.y - 3;
-	int width = ex - sx + 1;
-	int height = ey - sy + 1;
-	int wsx = sx - (w.frame ? 8 : 0);
-	int wsy = sy - (w.frame ? 8 : 0);
-	int wex = ex + (w.frame ? 8 : 0);
-	int wey = ey + (w.frame ? 8 : 0);
-	int wwidth = wex - wsx + 1;
-	int wheight = wey - wsy + 1;
-
-	// 画面退避
-	if (w.save) {
-		w.screen = CG(wsx, wsy, wwidth, wheight);
-		SDL_SetPaletteColors(w.screen.palette(), screen_palette->colors, 0, 256);
-
-		SDL_Rect rect = {wsx, wsy, wwidth, wheight};
-		SDL_BlitSurface(hBmpScreen[0], &rect, w.screen.surface(), NULL);
-	}
-
-	// メニュー表示
-	draw_window(wsx, wsy, wex, wey, w.frame, menu.frame_color, menu.back_color);
-	SDL_Rect src_rect = {0, 0, width, height};
-	SDL_Rect dst_rect = {sx, sy, width, height};
-	SDL_BlitSurface(hBmpScreen[2], &src_rect, hBmpScreen[0], &dst_rect);
-	box_line(0, sx, sy, ex, sy + menu.font_size + 3, menu.frame_color);
-	invalidate_screen(wsx, wsy, wwidth, wheight);
-}
-
-void AGS::redraw_menu_window(int index, int selected)
-{
-	Window &w = menu_w[index - 1];
-	int sx = w.sx;
-	int sy = w.sy;
-	int ex = w.ex;
-	int ey = menu_fix ? w.ey : sy + menu.pos.y - 3;
-	int width = ex - sx + 1;
-	int height = ey - sy + 1;
-
-	SDL_Rect src_rect = {0, 0, width, height};
-	SDL_Rect dst_rect = {sx, sy, width, height};
-	SDL_BlitSurface(hBmpScreen[2], &src_rect, hBmpScreen[0], &dst_rect);
-	box_line(0, sx, sy + (menu.font_size + 4) * selected, ex, sy + (menu.font_size + 4) * (selected + 1) - 1, menu.frame_color);
-	invalidate_screen(sx, sy, width, height);
-}
-
-void AGS::close_menu_window(int index)
-{
-	Window &w = menu_w[index - 1];
-	// 画面復帰
-	if (w.save && w.screen) {
-		SDL_SetSurfacePalette(hBmpScreen[0], w.screen.palette());
-		SDL_Rect rect = {w.screen.x, w.screen.y, w.screen.width(), w.screen.height()};
-		SDL_BlitSurface(w.screen.surface(), NULL, hBmpScreen[0], &rect);
-		invalidate_screen(w.screen.x, w.screen.y, w.screen.width(), w.screen.height());
-		SDL_SetSurfacePalette(hBmpScreen[0], screen_palette);
-	}
-}
-
-void AGS::get_menu_window_rect(int index, int* sx, int* sy, int* ex, int* ey)
-{
-	Window &w = menu_w[index - 1];
-	if (sx) *sx = w.sx;
-	if (sy) *sy = w.sy;
-	if (ex) *ex = w.ex;
-	if (ey) *ey = w.ey;
-}
-
-void AGS::draw_window(int sx, int sy, int ex, int ey, bool frame, uint8 frame_color, uint8 back_color)
-{
-	SDL_Rect rect = {sx, sy, ex - sx + 1, ey - sy + 1};
-	SDL_FillRect(hBmpScreen[0], &rect, back_color);
-
-	if(frame) {
-		SDL_Rect rects[] = {
-			{sx + 1, sy + 1, ex - sx - 1, 2},
-			{sx + 1, ey - 2, ex - sx - 1, 2},
-			{sx + 1, sy + 1, 2, ey - sy - 1},
-			{ex - 2, sy + 1, 2, ey - sy - 1},
-		};
-		SDL_FillRects(hBmpScreen[0], rects, 4, frame_color);
-		box_line(0, sx + 4, sy + 4, ex - 4, ey - 4, frame_color);
-	}
-	invalidate_screen(sx, sy, ex - sx + 1, ey - sy + 1);
-}
diff --git a/src/sys/cg.h b/src/sys/cg.h
new file mode 100644
index 0000000..193fd9e
--- /dev/null
+++ b/src/sys/cg.h
@@ -0,0 +1,42 @@
+/*
+	ALICE SOFT SYSTEM 3 for Win32
+
+	[ CG ]
+*/
+
+#ifndef _CG_H_
+#define _CG_H_
+
+#include <memory>
+#include <SDL.h>
+#include "common.h"
+
+inline uint8_t* surface_line(SDL_Surface* surface, int y)
+{
+	return static_cast<uint8*>(surface->pixels) + surface->pitch * y;
+}
+
+struct SurfaceDeleter {
+	void operator()(SDL_Surface* s) const noexcept {
+		if (s) SDL_FreeSurface(s);
+	}
+};
+
+struct CG {
+	std::unique_ptr<SDL_Surface, SurfaceDeleter> surface_;
+	int x;
+	int y;
+
+	CG() = default;
+	CG(int x, int y, int width, int height)
+		: surface_(SDL_CreateRGBSurfaceWithFormat(0, width, height, 8, SDL_PIXELFORMAT_INDEX8)),
+		  x(x), y(y) {}
+	explicit operator bool() const noexcept { return static_cast<bool>(surface_); }
+
+	SDL_Surface* surface() const { return surface_.get(); }
+	int width() const { return surface_->w; }
+	int height() const { return surface_->h; }
+	SDL_Palette* palette() const { return surface_->format->palette; }
+};
+
+#endif // _CG_H_
diff --git a/src/sys/nact.cpp b/src/sys/nact.cpp
index 270686e..425def5 100644
--- a/src/sys/nact.cpp
+++ b/src/sys/nact.cpp
@@ -70,6 +70,9 @@ NACT::NACT(const Config& config, const GameId& game_id)
 	mako = new MAKO(config, game_id);
 	msgskip = new MsgSkip();
 
+	init_windows();
+	ags->text.reset_pos(text_w[0].sx, text_w[0].sy + 2);
+
 	SDL_Init(SDL_INIT_GAMECONTROLLER);
 	for (int i = 0; i < SDL_NumJoysticks(); ++i) {
 		if (SDL_IsGameController(i)) {
@@ -330,7 +333,7 @@ void NACT::cmd_set_menu()
 		TRACE("$");
 	} else {
 		if (menu_items.empty()) {
-			ags->clear_menu_window();
+			clear_menu_window();
 		}
 		menu_items.emplace_back(sco.getw());
 		ags->draw_menu = true;
@@ -408,7 +411,7 @@ void NACT::cmd_a()
 		if (msgskip->get_flags() & MSGSKIP_STOP_ON_CLICK && get_key())
 			msgskip->activate(false);
 	} else if (show_push) {
-		ags->draw_push(text_window);
+		draw_push(text_window);
 	}
 
 	get_wheel();  // clear wheel input
@@ -429,7 +432,7 @@ void NACT::cmd_a()
 	}
 
 	// ウィンドウ更新
-	ags->clear_text_window(text_window, true);
+	clear_text_window(text_window, true);
 
 	if (game_id.is_system1_dps()) {
 		text_refresh = true;
@@ -449,8 +452,8 @@ void NACT::cmd_r()
 
 	TRACE("R");
 
-	// ウィンドウの表示範囲外の場合は改ページ
-	if(ags->return_text_line(text_window)) {
+	// If the text is outside the window, do a page break
+	if (return_text_line(text_window)) {
 		cmd_a();
 	}
 }
@@ -612,11 +615,11 @@ int NACT::menu_select(int num_items)
 		msgskip->activate(false);
 
 	// メニュー表示
-	ags->open_menu_window(menu_window);
+	open_menu_window(menu_window);
 
 	// マウス移動
 	int sx, sy, ex;
-	ags->get_menu_window_rect(menu_window, &sx, &sy, &ex, nullptr);
+	get_menu_window_rect(menu_window, &sx, &sy, &ex, nullptr);
 	int mx = ex - 16;
 	int my = sy + 10;
 	int height = ags->menu.font_size + 4;
@@ -654,7 +657,7 @@ int NACT::menu_select(int num_items)
 			int index = (my - sy) / height;
 			if(sx <= mx && mx <= ex && 0 <= index && index < num_items) {
 				current_index = index;
-				ags->redraw_menu_window(menu_window, current_index);
+				redraw_menu_window(menu_window, current_index);
 				selectable = true;
 			} else {
 				selectable = false;
@@ -669,7 +672,7 @@ int NACT::menu_select(int num_items)
 			} else if(val == 8) {
 				current_index = num_items - 1;
 			}
-			ags->redraw_menu_window(menu_window, current_index);
+			redraw_menu_window(menu_window, current_index);
 			selectable = true;
 		} else if(val == 16 && selectable) {
 			break;
@@ -680,9 +683,9 @@ int NACT::menu_select(int num_items)
 	}
 
 	// 画面更新
-	ags->close_menu_window(menu_window);
+	close_menu_window(menu_window);
 	if(clear_text) {
-		ags->clear_text_window(text_window, true);
+		clear_text_window(text_window, true);
 	}
 
 	return current_index;
diff --git a/src/sys/nact.h b/src/sys/nact.h
index fcb6890..31bdc13 100644
--- a/src/sys/nact.h
+++ b/src/sys/nact.h
@@ -14,6 +14,7 @@
 #include <SDL.h>
 #include "common.h"
 #include "config.h"
+#include "cg.h"
 #include "dri.h"
 #include "game_id.h"
 #include "scenario.h"
@@ -136,6 +137,38 @@ protected:
 	uint8_t cg_flags;
 	void load_cg(int page, int transparent);
 
+	// Window (B command)
+	struct Window {
+		int sx;
+		int sy;
+		int ex;
+		int ey;
+		bool frame;
+		bool save;
+		CG screen;
+		CG window;
+
+		void reset(int sx, int sy, int ex, int ey, bool frame, bool save);
+	};
+	Window menu_w[10];
+	Window text_w[10];
+	bool menu_fix = false;
+	const uint8_t* push_bitmap = nullptr;
+	void init_windows();
+
+	void clear_text_window(int index, bool erase);
+	bool return_text_line(int index);
+	void draw_push(int index);
+	void open_text_window(int index, bool erase);
+	void close_text_window(int index, bool update);
+
+	void clear_menu_window();
+	void open_menu_window(int index);
+	void redraw_menu_window(int index, int selected);
+	void close_menu_window(int index);
+	void get_menu_window_rect(int index, int* sx, int* sy, int* ex, int* ey);
+	int calculate_menu_max(int window);
+
 	struct MenuItem {
 		uint16_t addr;
 		uint8_t verb;
diff --git a/src/sys/nact_gakuenking.cpp b/src/sys/nact_gakuenking.cpp
index 0a96a3e..d4cf048 100644
--- a/src/sys/nact_gakuenking.cpp
+++ b/src/sys/nact_gakuenking.cpp
@@ -99,7 +99,7 @@ private:
 				ags->menu.back_color = ags->text.back_color =
 					(param == 1 || param == 2) ? 0 : 1;
 				text_window = param + 1;
-				ags->open_text_window(text_window, false);
+				open_text_window(text_window, false);
 			}
 			break;
 		case 26:
@@ -1368,16 +1368,16 @@ private:
 	static constexpr int PUSH_BITMAP_OFFSET = 0x08aa;
 	static constexpr int NR_PUSH_BITMAPS = 4;
 
-	uint8_t push_bitmap[NR_PUSH_BITMAPS][32] = {};
+	uint8_t push_bitmaps[NR_PUSH_BITMAPS][32] = {};
 
 	void load_push_bitmaps(const std::vector<uint8_t>& exe) {
-		memcpy(push_bitmap, &exe[PUSH_BITMAP_OFFSET], sizeof(push_bitmap));
+		memcpy(push_bitmaps, &exe[PUSH_BITMAP_OFFSET], sizeof(push_bitmaps));
 	}
 
 	void set_push_bitmap() {
 		int r = random(100);
 		r = r < NR_PUSH_BITMAPS ? r : 0;
-		ags->set_push_bitmap(fixed_shapes ? nullptr : push_bitmap[r]);
+		push_bitmap = fixed_shapes ? nullptr : push_bitmaps[r];
 	}
 
 	// --- I grid selection -------------------------------------------------
diff --git a/src/sys/nact_sys1.cpp b/src/sys/nact_sys1.cpp
index 874444f..88ab966 100644
--- a/src/sys/nact_sys1.cpp
+++ b/src/sys/nact_sys1.cpp
@@ -181,7 +181,7 @@ void NACT_Sys1::cmd_open_verb()
 
 	if (game_id.is(GameId::GAKUEN_SENKI))
 		menu_window = 1;
-	int menu_max = ags->calculate_menu_max(menu_window);
+	int menu_max = calculate_menu_max(menu_window);
 
 	for (const MenuItem& item : menu_items) {
 		chk[item.verb] = true;
@@ -192,7 +192,7 @@ top:
 	// メニュー項目の準備
 	int id[32], index = 0;
 
-	ags->clear_menu_window();
+	clear_menu_window();
 	ags->draw_menu = true;
 
 	if(cnt <= menu_max) {
@@ -245,7 +245,7 @@ top2:
 
 void NACT_Sys1::cmd_open_obj(int verb)
 {
-	int menu_max = ags->calculate_menu_max(menu_window);
+	int menu_max = calculate_menu_max(menu_window);
 
 	// 目的語メニューの表示
 	verb_obj = false;
@@ -274,7 +274,7 @@ top:
 	// メニュー項目の準備
 	int id[32], index = 0;
 
-	ags->clear_menu_window();
+	clear_menu_window();
 	ags->draw_menu = true;
 
 	if(cnt <= menu_max - 1) {
@@ -408,7 +408,7 @@ void NACT_Sys1::exec_y(int cmd, int param)
 {
 	switch(cmd) {
 	case 0:
-		ags->clear_text_window(text_window, true);
+		clear_text_window(text_window, true);
 		break;
 	case 1:
 		{
@@ -728,11 +728,11 @@ public:
 
 		switch (cmd) {
 		case 0:
-			ags->clear_text_window(text_window, true);
+			clear_text_window(text_window, true);
 			break;
 		case 1:
 			if (show_push) {
-				ags->draw_push(text_window);
+				draw_push(text_window);
 			}
 			for (;;) {
 				if (terminate) {
@@ -745,7 +745,7 @@ public:
 			}
 			sys_sleep(100);
 			wait_key_release(0x1f);
-			ags->clear_text_window(text_window, true);
+			clear_text_window(text_window, true);
 			break;
 		case 2:
 			if (param == 0) {
diff --git a/src/sys/nact_sys2.cpp b/src/sys/nact_sys2.cpp
index 8bf917d..6e6155b 100644
--- a/src/sys/nact_sys2.cpp
+++ b/src/sys/nact_sys2.cpp
@@ -274,7 +274,7 @@ void NACT_Sys2::cmd_open_verb()
 	// メニュー項目の準備
 	int id[32], index = 0;
 
-	ags->clear_menu_window();
+	clear_menu_window();
 	ags->draw_menu = true;
 
 	for(int i = 0; i < MAX_VERB; i++) {
@@ -325,7 +325,7 @@ void NACT_Sys2::cmd_open_obj(int verb)
 	// メニュー項目の準備
 	int id[32], index = 0;
 
-	ags->clear_menu_window();
+	clear_menu_window();
 	ags->draw_menu = true;
 
 	for(int i = 0; i < MAX_OBJ; i++) {
@@ -369,7 +369,7 @@ void NACT_Sys2::cmd_b()
 		if (game_id.is(GameId::AYUMI_FD) || game_id.is(GameId::AYUMI_HINT) || game_id.is(GameId::DRSTOP)) {
 			p5 = 1;
 		}
-		ags->set_menu_window(index, p1 * 8, p2, p3 * 8 - 1, p4, p5);
+		menu_w[index - 1].reset(p1 * 8, p2, p3 * 8 - 1, p4, menu_w[index - 1].frame, p5);
 		break;
 	case 2:
 		if (game_id.is(GameId::AYUMI_FD) || game_id.is(GameId::AYUMI_HINT) || game_id.is(GameId::DRSTOP)) {
@@ -378,11 +378,11 @@ void NACT_Sys2::cmd_b()
 //		if (game_id.is(GameId::PROG_FD)) {
 //			p1 = (index == 1 || index == 3);
 //		}
-		ags->set_menu_window_frame(index, p1);
+		menu_w[index - 1].frame = p1;
 		menu_window = index;
 		break;
 	case 3:
-		ags->set_text_window(index, p1 * 8, p2, p3 * 8 - 1, p4, p5);
+		text_w[index - 1].reset(p1 * 8, p2, p3 * 8 - 1, p4, text_w[index - 1].frame, p5);
 		break;
 	case 4:
 		if (game_id.is(GameId::AYUMI_FD) || game_id.is(GameId::AYUMI_HINT)) {
@@ -397,12 +397,12 @@ void NACT_Sys2::cmd_b()
 //			if (game_id.is(GameId::PROG_FD)) {
 //				p1 = (index == 1 || index == 3);
 //			} else
-			ags->set_text_window_frame(index, p1);
-			ags->open_text_window(index, p4 ? false : true);
+			text_w[index - 1].frame = p1;
+			open_text_window(index, p4 ? false : true);
 			text_window = index;
 		} else {
 			// ウィンドウ復帰
-			ags->close_text_window(index, text_window == index ? true : false);
+			close_text_window(index, text_window == index ? true : false);
 		}
 		break;
 	default:
@@ -693,7 +693,7 @@ void NACT_Sys2::cmd_y()
 
 	switch(cmd) {
 		case 1:
-			ags->clear_text_window(text_window, (param == 0) ? true : false);
+			clear_text_window(text_window, (param == 0) ? true : false);
 			break;
 		case 2:
 			if(param == 0) {
diff --git a/src/sys/nact_sys3.cpp b/src/sys/nact_sys3.cpp
index b537732..c3b7d8e 100644
--- a/src/sys/nact_sys3.cpp
+++ b/src/sys/nact_sys3.cpp
@@ -104,7 +104,7 @@ void NACT_Sys3::cmd_open_verb()
 	// メニュー項目の準備
 	int id[32], index = 0;
 
-	ags->clear_menu_window();
+	clear_menu_window();
 	ags->draw_menu = true;
 
 	for(int i = 0; i < MAX_VERB; i++) {
@@ -155,7 +155,7 @@ void NACT_Sys3::cmd_open_obj(int verb)
 	// メニュー項目の準備
 	int id[32], index = 0;
 
-	ags->clear_menu_window();
+	clear_menu_window();
 	ags->draw_menu = true;
 
 	for(int i = 0; i < MAX_OBJ; i++) {
@@ -200,24 +200,26 @@ void NACT_Sys3::cmd_b()
 		if (game_id.is(GameId::AYUMI_CD) || game_id.is(GameId::AYUMI_LIVE_256) || game_id.is(GameId::AYUMI_LIVE_FULL)) {
 			p5 = 1;
 		}
-		ags->set_menu_window(index, column ? p1 * 8 : p1 & 0xfff8, p2, column ? p3 * 8 - 1 : (p3 & 0xfff8) - 1, p4, p5);
+		menu_w[index - 1].reset(column ? p1 * 8 : p1 & 0xfff8, p2, column ? p3 * 8 - 1 : (p3 & 0xfff8) - 1, p4,
+								menu_w[index - 1].frame, p5);
 		break;
 	case 2:
-		ags->set_menu_window_frame(index, p1);
+		menu_w[index - 1].frame = p1;
 		menu_window = index;
 		break;
 	case 3:
-		ags->set_text_window(index, column ? p1 * 8 : p1 & 0xfff8, p2, column ? p3 * 8 - 1 : (p3 & 0xfff8) - 1, p4, p5);
+		text_w[index - 1].reset(column ? p1 * 8 : p1 & 0xfff8, p2, column ? p3 * 8 - 1 : (p3 & 0xfff8) - 1, p4,
+								text_w[index - 1].frame, p5);
 		break;
 	case 4:
 		if(p5 == 0) {
 			// ウィンドウ退避
-			ags->set_text_window_frame(index, p1);
-			ags->open_text_window(index, p4 ? false : true);
+			text_w[index - 1].frame = p1;
+			open_text_window(index, p4 ? false : true);
 			text_window = index;
 		} else {
 			// ウィンドウ復帰
-			ags->close_text_window(index, text_window == index ? true : false);
+			close_text_window(index, text_window == index ? true : false);
 		}
 		break;
 	default:
@@ -673,7 +675,7 @@ void NACT_Sys3::exec_y(int cmd, int param)
 {
 	switch(cmd) {
 		case 1:
-			ags->clear_text_window(text_window, (param == 0) ? true : false);
+			clear_text_window(text_window, (param == 0) ? true : false);
 			break;
 		case 2:
 			if(param == 0) {
@@ -932,7 +934,7 @@ void NACT_Sys3::exec_y(int cmd, int param)
 		case 233:
 			break;
 		case 234:
-			ags->menu_fix = param ? true : false;
+			menu_fix = param ? true : false;
 			break;
 		case 235:
 			break;
diff --git a/src/sys/nact_window.cpp b/src/sys/nact_window.cpp
index a3b743e..efa1629 100644
--- a/src/sys/nact_window.cpp
+++ b/src/sys/nact_window.cpp
@@ -8,6 +8,283 @@
 #include "ags.h"
 #include "fileio.h"
 
+void NACT::Window::reset(int sx, int sy, int ex, int ey, bool frame, bool save) {
+	this->sx = sx;
+	this->sy = sy;
+	this->ex = ex;
+	this->ey = ey;
+	this->frame = frame;
+	this->save = save;
+	screen.surface_.reset();
+	window.surface_.reset();
+}
+
+void NACT::init_windows()
+{
+	for (int i = 0; i < 10; i++) {
+		// ウィンドウの初期位置はシステムによって異なる
+		switch (game_id.game) {
+		case GameId::BUNKASAI:
+			text_w[i].reset(24, 304, 616, 384, false, false);
+			menu_w[i].reset(440, 18, 620, 178, true, true);
+			break;
+		case GameId::CRESCENT:
+			text_w[i].reset(24, 288, 616, 378, false, false);
+			// 本来は横メニュー
+			menu_w[i].reset(464, 50, 623, 240, true, true);
+			break;
+		case GameId::RANCE2:
+		case GameId::RANCE2_HINT:
+			text_w[i].reset(8, 285, 502, 396, false, false);
+			menu_w[i].reset(431, 19, 624, 181, false, true);
+			break;
+		case GameId::DPS:
+		case GameId::DPS_SG_FAHREN:
+		case GameId::DPS_SG_KATEI:
+		case GameId::DPS_SG_NOBUNAGA:
+		case GameId::DPS_SG2_ANTIQUE:
+		case GameId::DPS_SG2_IKENAI:
+		case GameId::DPS_SG2_AKAI:
+		case GameId::DPS_SG3_RABBIT:
+		case GameId::DPS_SG3_SHINKON:
+		case GameId::DPS_SG3_SOTSUGYOU:
+			text_w[i].reset(48, 288, 594, 393, false, false);
+			//menu_w[i].reset(48, 288, 584, 393, false, true);
+			menu_w[i].reset(48, 288, 594, 393, false, true);
+			break;
+		case GameId::FUKEI:
+			text_w[i].reset(44, 282, 593, 396, false, false);
+			menu_w[i].reset(460, 14, 635, 214, false, true);
+			break;
+		case GameId::INTRUDER:
+			text_w[i].reset(8, 280, 629, 393, false, false);
+			menu_w[i].reset(448, 136, 623, 340, true, true);
+			break;
+		case GameId::TENGU:
+			text_w[i].reset(44, 282, 593, 396, false, false);
+			menu_w[i].reset(452, 14, 627, 214, false, true);
+			break;
+		case GameId::TOUSHIN_HINT:
+			text_w[i].reset(8, 311, 623, 391, false, false);
+			menu_w[i].reset(452, 14, 627, 214, true, true);
+			break;
+		case GameId::LITTLE_VAMPIRE:
+			text_w[i].reset(8, 255, 615, 383, false, false);
+			menu_w[i].reset(448, 11, 615, game_id.language == ENGLISH ? 234 : 224, false, true);
+			break;
+		case GameId::YAKATA:
+			text_w[i].reset(48, 288, 594, 393, false, false);
+			menu_w[i].reset(452, 14, 627, 214, false, true);
+			break;
+		case GameId::DALK_HINT:
+			text_w[i].reset(24, 308, 376, 386, false, false);
+			menu_w[i].reset(404, 28, 604, 244, true, true);
+			break;
+		case GameId::RANCE3_HINT:
+			text_w[i].reset(104, 304, 615, 383, false, false);
+			menu_w[i].reset(464, 24, 623, 200, true, true);
+			break;
+		case GameId::YAKATA2:
+			text_w[i].reset(104, 304, 620, 382, false, false);
+			menu_w[i].reset(420, 28, 620, 244, true, true);
+			break;
+		case GameId::GAKUEN_SENKI:
+			text_w[i].reset(8, 260, 505, 384, false, false);
+			if (i == 1) {
+				menu_w[i].reset(128, 32, 337, 178, true, true);
+			} else {
+				menu_w[i].reset(288, 30, 433, 210, true, true);
+			}
+			break;
+		case GameId::GAKUEN_KING:
+			switch (i) {
+			default:
+			case 0: text_w[i].reset(112, 310, 623, 391, false, false); break;
+			case 1: text_w[i].reset(48, 310, 591, 391, false, false); break;
+			case 2: text_w[i].reset(0, 0, 639, 391, false, false); break;
+			case 3: text_w[i].reset(24, 310, 183, 391, false, false); break;
+			case 4: text_w[i].reset(464, 310, 623, 391, false, false); break;
+			}
+			switch (i) {
+			default:
+			case 0: menu_w[i].reset(416, 24, 591, 248, true, true); break;
+			case 1: menu_w[i].reset(32, 16, 191, 216, true, true); break;
+			case 2: menu_w[i].reset(448, 16, 607, 216, true, true); break;
+			case 3: menu_w[i].reset(32, 223, 191, 383, true, true); break;
+			case 4: menu_w[i].reset(448, 223, 607, 383, true, true); break;
+			}
+			break;
+		default:
+			text_w[i].reset(8, 311, 623, 391, true, false);
+			menu_w[i].reset(464, 80, 623, 240, true, true);
+			break;
+		}
+	}
+}
+
+void NACT::clear_text_window(int index, bool erase)
+{
+	Window& w = text_w[index - 1];
+
+	if (erase) {
+		if (w.frame && ags->is_faded()) {
+			ags->draw_window(w.sx - 8, w.sy - 8, w.ex + 8, w.ey + 8, true, ags->text.frame_color, ags->text.back_color);
+		} else {
+			ags->box_fill(0, w.sx, w.sy, w.ex, w.ey, ags->text.back_color);
+		}
+	}
+
+	ags->text.reset_pos(w.sx, w.sy + 2);
+}
+
+bool NACT::return_text_line(int index)
+{
+	ags->text.newline();
+	// Return true if the next line exceeds the bottom of the window
+	return ags->text.pos.y + ags->text.font_size > text_w[index - 1].ey;
+}
+
+void NACT::draw_push(int index)
+{
+	static const uint8_t builtin_bitmap[32] = {
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xe0, 0x00,
+		0x90, 0x00, 0x99, 0x74, 0xe9, 0x44, 0x89, 0x77,
+		0x89, 0x15, 0x87, 0x75, 0x00, 0x00, 0xff, 0xff
+	};
+
+	Window& w = text_w[index - 1];
+	int x = w.ex - 16;
+	int y = w.ey - 16;
+	ags->draw_gaiji(0, x, y, push_bitmap ? push_bitmap : builtin_bitmap, 16, ags->text.font_color);
+	ags->invalidate_screen(x, y, 16, 16);
+}
+
+void NACT::open_text_window(int index, bool erase)
+{
+	Window& w = text_w[index - 1];
+	int sx = w.sx - (w.frame ? 8 : 0);
+	int sy = w.sy - (w.frame ? 8 : 0);
+	int ex = w.ex + (w.frame ? 8 : 0);
+	int ey = w.ey + (w.frame ? 8 : 0);
+	int width = ex - sx + 1;
+	int height = ey - sy + 1;
+
+	if (game_id.is(GameId::PROG_CD) && !erase) {
+		// prostudent G オープニング画面化け対策
+		w.screen = CG();
+		w.window = CG();
+	}
+
+	if (w.save) {
+		w.screen = ags->save_rect(sx, sy, width, height);
+	}
+
+	if (erase) {
+		ags->draw_window(sx, sy, ex, ey, w.frame, ags->text.frame_color, ags->text.back_color);
+	} else if (w.save && w.window) {
+		ags->restore_rect(w.window);
+	}
+
+	ags->text.reset_pos(w.sx, w.sy + ags->text.line_space);
+}
+
+void NACT::close_text_window(int index, bool update)
+{
+	Window& w = text_w[index - 1];
+	int sx = w.sx - (w.frame ? 8 : 0);
+	int sy = w.sy - (w.frame ? 8 : 0);
+	int ex = w.ex + (w.frame ? 8 : 0);
+	int ey = w.ey + (w.frame ? 8 : 0);
+	int width = ex - sx + 1;
+	int height = ey - sy + 1;
+
+	if (w.save) {
+		w.window = ags->save_rect(sx, sy, width, height);
+	}
+
+	if (w.save && w.screen) {
+		ags->restore_rect(w.screen);
+	}
+
+	if (update) {
+		ags->text.reset_pos(w.sx, w.sy + ags->text.line_space);
+	}
+}
+
+void NACT::clear_menu_window()
+{
+	ags->box_fill(2, 0, 0, 639, 479, ags->menu.back_color);
+	ags->menu.reset_pos(2, 2);
+}
+
+void NACT::open_menu_window(int index)
+{
+	Window &w = menu_w[index - 1];
+	int sx = w.sx;
+	int sy = w.sy;
+	int ex = w.ex;
+	int ey = menu_fix ? w.ey : sy + ags->menu.pos.y - 3;
+	int width = ex - sx + 1;
+	int height = ey - sy + 1;
+	int wsx = sx - (w.frame ? 8 : 0);
+	int wsy = sy - (w.frame ? 8 : 0);
+	int wex = ex + (w.frame ? 8 : 0);
+	int wey = ey + (w.frame ? 8 : 0);
+	int wwidth = wex - wsx + 1;
+	int wheight = wey - wsy + 1;
+
+	if (w.save) {
+		w.screen = ags->save_rect(wsx, wsy, wwidth, wheight);
+	}
+
+	ags->draw_window(wsx, wsy, wex, wey, w.frame, ags->menu.frame_color, ags->menu.back_color);
+	ags->copy_screen(2, 0, 0, 0, width - 1, height - 1, sx, sy);
+	ags->box_line(0, sx, sy, ex, sy + ags->menu.font_size + 3, ags->menu.frame_color);
+	ags->invalidate_screen(wsx, wsy, wwidth, wheight);
+}
+
+void NACT::redraw_menu_window(int index, int selected)
+{
+	Window &w = menu_w[index - 1];
+	int sx = w.sx;
+	int sy = w.sy;
+	int ex = w.ex;
+	int ey = menu_fix ? w.ey : sy + ags->menu.pos.y - 3;
+	int width = ex - sx + 1;
+	int height = ey - sy + 1;
+
+	ags->copy_screen(2, 0, 0, 0, width - 1, height - 1, sx, sy);
+	ags->box_line(0, sx, sy + (ags->menu.font_size + 4) * selected, ex, sy + (ags->menu.font_size + 4) * (selected + 1) - 1, ags->menu.frame_color);
+	ags->invalidate_screen(sx, sy, width, height);
+}
+
+void NACT::close_menu_window(int index)
+{
+	Window &w = menu_w[index - 1];
+	if (w.save && w.screen) {
+		ags->restore_rect(w.screen);
+	}
+}
+
+void NACT::get_menu_window_rect(int index, int* sx, int* sy, int* ex, int* ey)
+{
+	Window &w = menu_w[index - 1];
+	if (sx) *sx = w.sx;
+	if (sy) *sy = w.sy;
+	if (ex) *ex = w.ex;
+	if (ey) *ey = w.ey;
+}
+
+int NACT::calculate_menu_max(int window)
+{
+	if (game_id.is(GameId::INTRUDER))
+		return 6;
+	if (game_id.is(GameId::GAKUEN_SENKI))
+		return (menu_w[window - 1].ey - menu_w[window - 1].sy) / (ags->menu.font_size + 4);
+	return 11;
+}
+
 void NACT::load_display_state(FILEIO* fio)
 {
 	ags->menu.font_size = fio->getw();
@@ -29,7 +306,7 @@ void NACT::load_display_state(FILEIO* fio)
 		int ey = fio->getw();
 		bool save = fio->getw() ? true : false;
 		bool frame = fio->getw() ? true : false;
-		ags->menu_w[i].reset(sx, sy, ex, ey, frame, save);
+		menu_w[i].reset(sx, sy, ex, ey, frame, save);
 		fio->getw();
 		fio->getw();
 	}
@@ -40,7 +317,7 @@ void NACT::load_display_state(FILEIO* fio)
 		int ey = fio->getw();
 		bool save = fio->getw() ? true : false;
 		bool frame = fio->getw() ? true : false;
-		ags->text_w[i].reset(sx, sy, ex, ey, frame, save);
+		text_w[i].reset(sx, sy, ex, ey, frame, save);
 		fio->getw();
 		fio->getw();
 	}
@@ -58,22 +335,22 @@ void NACT::save_display_state(FILEIO* fio)
 	fio->putw(ags->text.frame_color);
 	fio->putw(ags->text.back_color);
 	for (int i = 0; i < 10; i++) {
-		fio->putw(ags->menu_w[i].sx);
-		fio->putw(ags->menu_w[i].sy);
-		fio->putw(ags->menu_w[i].ex);
-		fio->putw(ags->menu_w[i].ey);
-		fio->putw(ags->menu_w[i].save ? 1 : 0);
-		fio->putw(ags->menu_w[i].frame ? 1 : 0);
+		fio->putw(menu_w[i].sx);
+		fio->putw(menu_w[i].sy);
+		fio->putw(menu_w[i].ex);
+		fio->putw(menu_w[i].ey);
+		fio->putw(menu_w[i].save ? 1 : 0);
+		fio->putw(menu_w[i].frame ? 1 : 0);
 		fio->putw(0);
 		fio->putw(0);
 	}
 	for (int i = 0; i < 10; i++) {
-		fio->putw(ags->text_w[i].sx);
-		fio->putw(ags->text_w[i].sy);
-		fio->putw(ags->text_w[i].ex);
-		fio->putw(ags->text_w[i].ey);
-		fio->putw(ags->text_w[i].save ? 1 : 0);
-		fio->putw(ags->text_w[i].frame ? 1 : 0);
+		fio->putw(text_w[i].sx);
+		fio->putw(text_w[i].sy);
+		fio->putw(text_w[i].ex);
+		fio->putw(text_w[i].ey);
+		fio->putw(text_w[i].save ? 1 : 0);
+		fio->putw(text_w[i].frame ? 1 : 0);
 		fio->putw(0);
 		fio->putw(0);
 	}