diff --git a/src/window_manager.cc b/src/window_manager.cc
index 217ea94..af5f023 100644
--- a/src/window_manager.cc
+++ b/src/window_manager.cc
@@ -2,11 +2,9 @@
 
 #include "color.h"
 #include "core.h"
-#include "db.h"
 #include "debug.h"
 #include "draw.h"
 #include "memory.h"
-#include "palette.h"
 #include "text_font.h"
 #include "win32.h"
 #include "window_manager_private.h"
@@ -16,22 +14,50 @@
 
 #include <algorithm>
 
+#define MAX_WINDOW_COUNT (50)
+
+// The maximum number of radio groups.
+#define RADIO_GROUP_LIST_CAPACITY (64)
+
+static void windowFree(int win);
+static void _win_buffering(bool a1);
+static void _win_move(int win_index, int x, int y);
+static void _GNW_win_refresh(Window* window, Rect* rect, unsigned char* a3);
+static void _win_clip(Window* window, RectListNode** rect, unsigned char* a3);
+static void _win_drag(int win);
+static void _refresh_all(Rect* rect, unsigned char* a2);
+static Button* buttonGetButton(int btn, Window** out_win);
+static void _win_text(int win, char** fileNameList, int fileNameListLength, int maxWidth, int x, int y, int flags);
+static int paletteOpenFileImpl(const char* path, int flags);
+static int paletteReadFileImpl(int fd, void* buf, size_t count);
+static int paletteCloseFileImpl(int fd);
+static int _win_register_button_image(int btn, unsigned char* up, unsigned char* down, unsigned char* hover, int a5);
+static Button* buttonCreateInternal(int win, int x, int y, int width, int height, int mouseEnterEventCode, int mouseExitEventCode, int mouseDownEventCode, int mouseUpEventCode, int flags, unsigned char* up, unsigned char* dn, unsigned char* hover);
+static int _GNW_check_buttons(Window* window, int* out_a2);
+static bool _button_under_mouse(Button* button, Rect* rect);
+static int _win_last_button_winID();
+static void buttonFree(Button* ptr);
+static int _win_group_check_buttons(int a1, int* a2, int a3, void (*a4)(int));
+static int _button_check_group(Button* button);
+static void _button_draw(Button* button, Window* window, unsigned char* data, int a4, Rect* a5, int a6);
+static void _GNW_button_refresh(Window* window, Rect* rect);
+
 // 0x50FA30
-char _path_patches[] = "";
+static char _path_patches[] = "";
 
 // 0x51E3D8
-bool _GNW95_already_running = false;
+static bool _GNW95_already_running = false;
 
 #ifdef _WIN32
 // 0x51E3DC
-HANDLE _GNW95_title_mutex = INVALID_HANDLE_VALUE;
+static HANDLE _GNW95_title_mutex = INVALID_HANDLE_VALUE;
 #endif
 
 // 0x51E3E0
 bool gWindowSystemInitialized = false;
 
 // 0x51E3E4
-int _GNW_wcolor[6] = {
+static int _GNW_wcolor[6] = {
     0,
     0,
     0,
@@ -41,46 +67,46 @@ int _GNW_wcolor[6] = {
 };
 
 // 0x51E3FC
-unsigned char* _screen_buffer = NULL;
+static unsigned char* _screen_buffer = NULL;
 
 // 0x51E400
-bool _insideWinExit = false;
+static bool _insideWinExit = false;
 
 // 0x51E404
-int _last_button_winID = -1;
+static int _last_button_winID = -1;
 
 // 0x6ADD90
-int gOrderedWindowIds[MAX_WINDOW_COUNT];
+static int gOrderedWindowIds[MAX_WINDOW_COUNT];
 
 // 0x6ADE58
-Window* gWindows[MAX_WINDOW_COUNT];
+static Window* gWindows[MAX_WINDOW_COUNT];
 
 // 0x6ADF20
-VideoSystemExitProc* gVideoSystemExitProc;
+static VideoSystemExitProc* gVideoSystemExitProc;
 
 // 0x6ADF24
-int gWindowsLength;
+static int gWindowsLength;
 
 // 0x6ADF28
-int _window_flags;
+static int _window_flags;
 
 // 0x6ADF2C
-bool _buffering;
+static bool _buffering;
 
 // 0x6ADF30
-int _bk_color;
+static int _bk_color;
 
 // 0x6ADF34
-VideoSystemInitProc* gVideoSystemInitProc;
+static VideoSystemInitProc* gVideoSystemInitProc;
 
 // 0x6ADF38
-int _doing_refresh_all;
+static int _doing_refresh_all;
 
 // 0x6ADF3C
-void* _GNW_texture;
+static void* _GNW_texture;
 
 // 0x6ADF40
-RadioGroup gRadioGroups[RADIO_GROUP_LIST_CAPACITY];
+static RadioGroup gRadioGroups[RADIO_GROUP_LIST_CAPACITY];
 
 // 0x4D5C30
 int windowManagerInit(VideoSystemInitProc* videoSystemInitProc, VideoSystemExitProc* videoSystemExitProc, int a3)
diff --git a/src/window_manager.h b/src/window_manager.h
index 99397f4..42b4b5e 100644
--- a/src/window_manager.h
+++ b/src/window_manager.h
@@ -11,11 +11,6 @@
 #include <windows.h>
 #endif
 
-#define MAX_WINDOW_COUNT (50)
-
-// The maximum number of radio groups.
-#define RADIO_GROUP_LIST_CAPACITY (64)
-
 // The maximum number of buttons in one radio group.
 #define RADIO_GROUP_BUTTON_LIST_CAPACITY (64)
 
@@ -155,36 +150,12 @@ typedef struct RadioGroup {
 typedef int(VideoSystemInitProc)();
 typedef void(VideoSystemExitProc)();
 
-extern char _path_patches[];
-
-extern bool _GNW95_already_running;
-#ifdef _WIN32
-extern HANDLE _GNW95_title_mutex;
-#endif
 extern bool gWindowSystemInitialized;
-extern int _GNW_wcolor[6];
-extern unsigned char* _screen_buffer;
-extern bool _insideWinExit;
-extern int _last_button_winID;
-
-extern int gOrderedWindowIds[MAX_WINDOW_COUNT];
-extern Window* gWindows[MAX_WINDOW_COUNT];
-extern VideoSystemExitProc* gVideoSystemExitProc;
-extern int gWindowsLength;
-extern int _window_flags;
-extern bool _buffering;
-extern int _bk_color;
-extern VideoSystemInitProc* gVideoSystemInitProc;
-extern int _doing_refresh_all;
-extern void* _GNW_texture;
-extern RadioGroup gRadioGroups[RADIO_GROUP_LIST_CAPACITY];
 
 int windowManagerInit(VideoSystemInitProc* videoSystemInitProc, VideoSystemExitProc* videoSystemExitProc, int a3);
 void windowManagerExit(void);
 int windowCreate(int x, int y, int width, int height, int a4, int flags);
 void windowDestroy(int win);
-void windowFree(int win);
-void _win_buffering(bool a1);
 void windowDrawBorder(int win);
 void windowDrawText(int win, char* str, int a3, int x, int y, int a6);
 void windowDrawLine(int win, int left, int top, int right, int bottom, int color);
@@ -192,15 +163,10 @@ void windowDrawRect(int win, int left, int top, int right, int bottom, int color
 void windowFill(int win, int x, int y, int width, int height, int a6);
 void windowUnhide(int win);
 void windowHide(int win);
-void _win_move(int win_index, int x, int y);
 void windowRefresh(int win);
 void windowRefreshRect(int win, const Rect* rect);
-void _GNW_win_refresh(Window* window, Rect* rect, unsigned char* a3);
 void windowRefreshAll(Rect* rect);
-void _win_clip(Window* window, RectListNode** rect, unsigned char* a3);
-void _win_drag(int win);
 void _win_get_mouse_buf(unsigned char* a1);
-void _refresh_all(Rect* rect, unsigned char* a2);
 Window* windowGetWindow(int win);
 unsigned char* windowGetBuffer(int win);
 int windowGetAtPoint(int x, int y);
@@ -208,37 +174,22 @@ int windowGetWidth(int win);
 int windowGetHeight(int win);
 int windowGetRect(int win, Rect* rect);
 int _win_check_all_buttons();
-Button* buttonGetButton(int btn, Window** out_win);
 int _GNW_check_menu_bars(int a1);
-void _win_text(int win, char** fileNameList, int fileNameListLength, int maxWidth, int x, int y, int flags);
 void programWindowSetTitle(const char* title);
-int paletteOpenFileImpl(const char* path, int flags);
-int paletteReadFileImpl(int fd, void* buf, size_t count);
-int paletteCloseFileImpl(int fd);
 bool showMesageBox(const char* str);
 int buttonCreate(int win, int x, int y, int width, int height, int mouseEnterEventCode, int mouseExitEventCode, int mouseDownEventCode, int mouseUpEventCode, unsigned char* up, unsigned char* dn, unsigned char* hover, int flags);
 int _win_register_button_disable(int btn, unsigned char* up, unsigned char* down, unsigned char* hover);
-int _win_register_button_image(int btn, unsigned char* up, unsigned char* down, unsigned char* hover, int a5);
 int buttonSetMouseCallbacks(int btn, ButtonCallback* mouseEnterProc, ButtonCallback* mouseExitProc, ButtonCallback* mouseDownProc, ButtonCallback* mouseUpProc);
 int buttonSetRightMouseCallbacks(int btn, int rightMouseDownEventCode, int rightMouseUpEventCode, ButtonCallback* rightMouseDownProc, ButtonCallback* rightMouseUpProc);
 int buttonSetCallbacks(int btn, ButtonCallback* onPressed, ButtonCallback* onUnpressed);
 int buttonSetMask(int btn, unsigned char* mask);
-Button* buttonCreateInternal(int win, int x, int y, int width, int height, int mouseEnterEventCode, int mouseExitEventCode, int mouseDownEventCode, int mouseUpEventCode, int flags, unsigned char* up, unsigned char* dn, unsigned char* hover);
 bool _win_button_down(int btn);
-int _GNW_check_buttons(Window* window, int* out_a2);
-bool _button_under_mouse(Button* button, Rect* rect);
 int buttonGetWindowId(int btn);
-int _win_last_button_winID();
 int buttonDestroy(int btn);
-void buttonFree(Button* ptr);
 int buttonEnable(int btn);
 int buttonDisable(int btn);
 int _win_set_button_rest_state(int btn, bool a2, int a3);
-int _win_group_check_buttons(int a1, int* a2, int a3, void (*a4)(int));
 int _win_group_radio_buttons(int a1, int* a2);
-int _button_check_group(Button* button);
-void _button_draw(Button* button, Window* window, unsigned char* data, int a4, Rect* a5, int a6);
-void _GNW_button_refresh(Window* window, Rect* rect);
 int _win_button_press_and_release(int btn);
 
 #endif /* WINDOW_MANAGER_H */