Index: src/gfx.cpp
===================================================================
--- src/gfx.cpp	(revision 8739)
+++ src/gfx.cpp	(working copy)
@@ -38,6 +38,7 @@
 byte _pause;
 int _pal_first_dirty;
 int _pal_last_dirty;
+bool _supports_seperate_fullscreen_res = false;
 
 Colour _cur_palette[256];
 byte _stringwidth_table[FS_END][224];
Index: src/gfx.h
===================================================================
--- src/gfx.h	(revision 8739)
+++ src/gfx.h	(working copy)
@@ -156,6 +156,8 @@
 extern uint16 _cur_resolution[2];
 extern Colour _cur_palette[256];
 
+extern bool _supports_seperate_fullscreen_res;
+
 void HandleKeypress(uint32 key);
 void HandleMouseEvents(void);
 void CSleep(int milliseconds);
Index: src/main_gui.cpp
===================================================================
--- src/main_gui.cpp	(revision 8739)
+++ src/main_gui.cpp	(working copy)
@@ -2459,6 +2459,13 @@
 
 void GameSizeChanged(void)
 {
+	if (!_supports_seperate_fullscreen_res) {
+		//maintain compatibility since these are the values that are now
+		//persisted instead of _cur_resolution.
+		_windowed_size[0] = _fullscreen_resolution[0] = _screen.width;
+		_windowed_size[1] = _fullscreen_resolution[1] = _screen.height;
+	}
+
 	_cur_resolution[0] = _screen.width;
 	_cur_resolution[1] = _screen.height;
 	RelocateAllWindows(_screen.width, _screen.height);
@@ -2474,3 +2481,4 @@
 
 
 
+
Index: src/openttd.cpp
===================================================================
--- src/openttd.cpp	(revision 8739)
+++ src/openttd.cpp	(working copy)
@@ -445,7 +445,10 @@
 	if (!StrEmpty(musicdriver)) ttd_strlcpy(_ini_musicdriver, musicdriver, sizeof(_ini_musicdriver));
 	if (!StrEmpty(sounddriver)) ttd_strlcpy(_ini_sounddriver, sounddriver, sizeof(_ini_sounddriver));
 	if (!StrEmpty(videodriver)) ttd_strlcpy(_ini_videodriver, videodriver, sizeof(_ini_videodriver));
-	if (resolution[0] != 0) { _cur_resolution[0] = resolution[0]; _cur_resolution[1] = resolution[1]; }
+	if (resolution[0] != 0) { 
+		_cur_resolution[0] = _windowed_size[0] = _fullscreen_resolution[0] = resolution[0];
+		_cur_resolution[1] = _windowed_size[1] = _fullscreen_resolution[1] = resolution[1];
+	}
 	if (startyear != INVALID_YEAR) _patches_newgame.starting_year = startyear;
 	if (generation_seed != GENERATE_NEW_SEED) _patches_newgame.generation_seed = generation_seed;
 
@@ -1813,3 +1816,4 @@
 HalSoundDriver *_sound_driver;
 HalVideoDriver *_video_driver;
 
+
Index: src/settings.cpp
===================================================================
--- src/settings.cpp	(revision 8739)
+++ src/settings.cpp	(working copy)
@@ -1190,7 +1190,8 @@
 	  SDTG_STR("musicdriver",      SLE_STRB,C|S,0, _ini_musicdriver,       NULL,    STR_NULL, NULL),
 	  SDTG_STR("sounddriver",      SLE_STRB,C|S,0, _ini_sounddriver,       NULL,    STR_NULL, NULL),
 	  SDTG_STR("language",         SLE_STRB, S, 0, _dynlang.curr_file,     NULL,    STR_NULL, NULL),
-	 SDTG_LIST("resolution",     SLE_UINT16, S, 0, _cur_resolution,   "640,480",    STR_NULL, NULL),
+	 SDTG_LIST("window_size",    SLE_UINT16, S, 0, _windowed_size,        "0,0",    STR_NULL, NULL), //if the first element is 0, then it will be set from _fullscreen_resolution
+	 SDTG_LIST("resolution",     SLE_UINT16, S, 0, _fullscreen_resolution,"640,480",STR_NULL, NULL),
 	  SDTG_STR("screenshot_format",SLE_STRB, S, 0, _screenshot_format_name,NULL,    STR_NULL, NULL),
 	  SDTG_STR("savegame_format",  SLE_STRB, S, 0, _savegame_format,       NULL,    STR_NULL, NULL),
 	 SDTG_BOOL("rightclick_emulate",         S, 0, _rightclick_emulate,   false,    STR_NULL, NULL),
@@ -1840,6 +1841,22 @@
 		_patches_newgame.pf_maxdepth = 48;
 		_patches_newgame.pf_maxlength = 4096;
 	}
+
+	//Set window size from fullscreen size if windowed size isn't specified (older config)
+	if (_windowed_size[0] == 0) {
+		_windowed_size[0] = _fullscreen_resolution[0];
+		_windowed_size[1] = _fullscreen_resolution[1];	
+	}
+
+	//restore the correct resolution to _cur_resolution. This is where everything else will
+	//be expecting to find these values when loading.
+	if (_fullscreen) {
+		_cur_resolution[0] = _fullscreen_resolution[0];
+		_cur_resolution[1] = _fullscreen_resolution[1];
+	} else {
+		_cur_resolution[0] = _windowed_size[0];
+		_cur_resolution[1] = _windowed_size[1];
+	}
 }
 
 void UpdatePatches(void)
Index: src/settings_gui.cpp
===================================================================
--- src/settings_gui.cpp	(revision 8739)
+++ src/settings_gui.cpp	(working copy)
@@ -67,10 +67,9 @@
 static int GetCurRes(void)
 {
 	int i;
-
 	for (i = 0; i != _num_resolutions; i++) {
-		if (_resolutions[i][0] == _screen.width &&
-				_resolutions[i][1] == _screen.height) {
+		if (_resolutions[i][0] == _fullscreen_resolution[0]
+			&& _resolutions[i][1] == _fullscreen_resolution[1]) {
 			break;
 		}
 	}
Index: src/variables.h
===================================================================
--- src/variables.h	(revision 8739)
+++ src/variables.h	(working copy)
@@ -331,6 +331,9 @@
 VARDEF uint16 _resolutions[32][2];
 VARDEF uint16 _cur_resolution[2];
 
+VARDEF uint16 _windowed_size[2];
+VARDEF uint16 _fullscreen_resolution[2];
+
 VARDEF char _savegame_format[8];
 
 VARDEF char *_config_file;
Index: src/video/win32_v.cpp
===================================================================
--- src/video/win32_v.cpp	(revision 8739)
+++ src/video/win32_v.cpp	(working copy)
@@ -22,8 +22,6 @@
 	HPALETTE gdi_palette;
 	int width;
 	int height;
-	int width_org;
-	int height_org;
 	bool fullscreen;
 	bool double_size;
 	bool has_focus;
@@ -133,6 +131,13 @@
 
 static void ClientSizeChanged(int w, int h)
 {
+	//store the physical window size before pixel doubling, etc.
+	//don't update the window size when maximising, maximized is stored seperatly
+	if (!_fullscreen && !_window_maximize) {
+		_windowed_size[0] = w;
+		_windowed_size[1] = h;
+	}
+
 	if (_wnd.double_size) {
 		w /= 2;
 		h /= 2;
@@ -537,10 +542,20 @@
 
 static void MakeWindow(bool full_screen)
 {
+	int target_width;
+	int target_height;
+
 	_fullscreen = full_screen;
-
 	_wnd.double_size = _double_size && !full_screen;
 
+	if (full_screen) {
+		target_width = _fullscreen_resolution[0];
+		target_height = _fullscreen_resolution[1];
+	} else {
+		target_width = _windowed_size[0];
+		target_height = _windowed_size[1];
+	}
+
 	// recreate window?
 	if ((full_screen || _wnd.fullscreen) && _wnd.main_wnd) {
 		DestroyWindow(_wnd.main_wnd);
@@ -561,8 +576,8 @@
 			DM_PELSHEIGHT |
 			(_display_hz != 0 ? DM_DISPLAYFREQUENCY : 0);
 		settings.dmBitsPerPel = _fullscreen_bpp;
-		settings.dmPelsWidth  = _wnd.width_org;
-		settings.dmPelsHeight = _wnd.height_org;
+		settings.dmPelsWidth  = target_width;
+		settings.dmPelsHeight = target_height;
 		settings.dmDisplayFrequency = _display_hz;
 
 		if (ChangeDisplaySettings(&settings, CDS_FULLSCREEN) != DISP_CHANGE_SUCCESSFUL) {
@@ -584,12 +599,12 @@
 		_wnd.fullscreen = full_screen;
 		if (_wnd.fullscreen) {
 			style = WS_POPUP;
-			SetRect(&r, 0, 0, _wnd.width_org, _wnd.height_org);
+			SetRect(&r, 0, 0, target_width, target_height);
 		} else {
 			style = WS_OVERLAPPEDWINDOW;
 			/* On window creation, check if we were in maximize mode before */
 			if (_window_maximize) showstyle = SW_SHOWMAXIMIZED;
-			SetRect(&r, 0, 0, _wnd.width, _wnd.height);
+			SetRect(&r, 0, 0, target_width, target_height);
 		}
 
 #if !defined(WINCE)
@@ -737,9 +752,7 @@
 
 	FindResolutions();
 
-	// fullscreen uses those
-	_wnd.width_org = _cur_resolution[0];
-	_wnd.height_org = _cur_resolution[1];
+	_supports_seperate_fullscreen_res = true;
 
 	AllocateDibSection(_cur_resolution[0], _cur_resolution[1]);
 	MarkWholeScreenDirty();
@@ -879,11 +892,13 @@
 
 static bool Win32GdiChangeRes(int w, int h)
 {
-	_wnd.width = _wnd.width_org = w;
-	_wnd.height = _wnd.height_org = h;
+	_fullscreen_resolution[0] = w;
+	_fullscreen_resolution[1] = h;
+	
+	if (_fullscreen) {
+		MakeWindow(true); // _wnd.fullscreen screws up ingame resolution switching
+	}
 
-	MakeWindow(_fullscreen); // _wnd.fullscreen screws up ingame resolution switching
-
 	return true;
 }