diff --git a/src/game.c b/src/game.c
index c6232ae35c..8aa081caee 100644
--- a/src/game.c
+++ b/src/game.c
@@ -229,7 +229,7 @@ void game_handle_input()
 	}
 
 	for (w = RCT2_ADDRESS(RCT2_ADDRESS_WINDOW_LIST, rct_window); w < RCT2_GLOBAL(RCT2_ADDRESS_NEW_WINDOW_PTR, rct_window*); w++)
-		RCT2_CALLPROC_X(w->event_handlers[WE_UNKNOWN_08], 0, 0, 0, 0, (int)w, 0, 0);
+		RCT2_CALLPROC_X(w->event_handlers[WE_UNKNOWN_08], 0, 0, 0, 0,(int) w, 0, 0);
 }
 
 /**
diff --git a/src/window.c b/src/window.c
index 1b995f32f8..2a79a9d76f 100644
--- a/src/window.c
+++ b/src/window.c
@@ -99,7 +99,16 @@ rct_widget *window_get_scroll_widget(rct_window *w, int scrollIndex)
 
 	return NULL;
 }
-
+static void RCT2_CALLPROC_WE_UPDATE(int address, rct_window* w)
+{
+	__asm {
+			push address
+			push w
+			mov esi, w
+			call[esp + 4]
+			add esp, 8
+	}
+}
 /**
  * 
  *  rct2: 0x006ED7B0
@@ -111,7 +120,7 @@ void window_dispatch_update_all()
 	RCT2_GLOBAL(0x01423604, sint32)++;
 	RCT2_GLOBAL(RCT2_ADDRESS_TOOLTIP_NOT_SHOWN_TICKS, sint16)++;
 	for (w = RCT2_LAST_WINDOW; w >= RCT2_FIRST_WINDOW; w--)
-		RCT2_CALLPROC_X(w->event_handlers[WE_UPDATE], 0, 0, 0, 0, (int)w, 0, 0);
+		RCT2_CALLPROC_WE_UPDATE(w->event_handlers[WE_UPDATE], w);
 
 	RCT2_CALLPROC_EBPSAFE(0x006EE411);	// handle_text_input
 }
@@ -142,7 +151,7 @@ void window_update_all()
 	if (RCT2_GLOBAL(0x009DEB7C, sint16) >= 1000) {
 		RCT2_GLOBAL(0x009DEB7C, sint16) = 0;
 		for (w = RCT2_LAST_WINDOW; w >= RCT2_FIRST_WINDOW; w--)
-			RCT2_CALLPROC_X(w->event_handlers[WE_UNKNOWN_07], 0, 0, 0, 0, (int)w, 0, 0);
+			RCT2_CALLPROC_X(w->event_handlers[WE_UNKNOWN_07], 0, 0, 0, 0, (int) w, 0, 0);
 	}
 
 	// Border flash invalidation
diff --git a/src/window_cheats.c b/src/window_cheats.c
index 8dfbb32e21..c9500f65f1 100644
--- a/src/window_cheats.c
+++ b/src/window_cheats.c
@@ -79,7 +79,7 @@ static rct_widget *window_cheats_page_widgets[] = {
 static void window_cheats_emptysub() { }
 static void window_cheats_money_mouseup();
 static void window_cheats_guests_mouseup();
-static void window_cheats_update();
+static void window_cheats_update(rct_window *w);
 static void window_cheats_invalidate();
 static void window_cheats_paint();
 static void window_cheats_set_page(rct_window *w, int page);
@@ -241,11 +241,11 @@ static void window_cheats_guests_mouseup()
 	}
 }
 
-static void window_cheats_update()
+static void window_cheats_update(rct_window *w)
 {
-	rct_window *w;
+	rct_window *w2;
 
-	__asm mov w, esi
+	__asm mov w2, esi
 
 	w->var_48E++;
 	widget_invalidate(w->classification, w->number, WIDX_TAB_1+w->page);
diff --git a/src/window_clear_scenery.c b/src/window_clear_scenery.c
index 81cc447c78..9b8bde8727 100644
--- a/src/window_clear_scenery.c
+++ b/src/window_clear_scenery.c
@@ -49,7 +49,7 @@ static int window_clear_scenery_should_close();
 static void window_clear_scenery_emptysub() { }
 static void window_clear_scenery_close();
 static void window_clear_scenery_mouseup();
-static void window_clear_scenery_update();
+static void window_clear_scenery_update(rct_window *w);
 static void window_clear_scenery_invalidate();
 static void window_clear_scenery_paint();
 
@@ -168,12 +168,8 @@ static void window_clear_scenery_mouseup()
  *
  *  rct2: 0x0068E205
  */
-static void window_clear_scenery_update()
+static void window_clear_scenery_update(rct_window *w)
 {
-	rct_window *w;
-
-	__asm mov w, esi
-
 	// Close window if another tool is open
 	if (window_clear_scenery_should_close())
 		window_close(w);
diff --git a/src/window_footpath.c b/src/window_footpath.c
index cbb8dc144b..429baa8248 100644
--- a/src/window_footpath.c
+++ b/src/window_footpath.c
@@ -113,7 +113,7 @@ static void window_footpath_close();
 static void window_footpath_mouseup();
 static void window_footpath_mousedown();
 static void window_footpath_dropdown();
-static void window_footpath_update();
+static void window_footpath_update(rct_window *w);
 static void window_footpath_toolupdate();
 static void window_footpath_tooldown();
 static void window_footpath_tooldrag();
@@ -475,12 +475,8 @@ static void window_footpath_toolup()
  * 
  *  rct2: 0x006A84BB
  */
-static void window_footpath_update()
+static void window_footpath_update(rct_window *w)
 {
-	rct_window *w;
-
-	__asm mov w, esi
-
 	// Invalidate construct button
 	widget_invalidate(WC_FOOTPATH, 0, WIDX_CONSTRUCT);
 
diff --git a/src/window_guest_list.c b/src/window_guest_list.c
index a8e66cbca1..bbdcbcca56 100644
--- a/src/window_guest_list.c
+++ b/src/window_guest_list.c
@@ -75,7 +75,7 @@ static void window_guest_list_mouseup();
 static void window_guest_list_resize();
 static void window_guest_list_mousedown();
 static void window_guest_list_dropdown();
-static void window_guest_list_update();
+static void window_guest_list_update(rct_window *w);
 static void window_guest_list_scrollgetsize();
 static void window_guest_list_scrollmousedown();
 static void window_guest_list_scrollmouseover();
@@ -327,12 +327,8 @@ static void window_guest_list_dropdown()
  * 
  *  rct2: 0x00699E54
  */
-static void window_guest_list_update()
+static void window_guest_list_update(rct_window *w)
 {
-	rct_window *w;
-
-	__asm mov w, esi
-
 	if (RCT2_GLOBAL(0x00F1AF20, uint16) != 0)
 		RCT2_GLOBAL(0x00F1AF20, uint16)--;
 	w->var_490++;
diff --git a/src/window_land.c b/src/window_land.c
index 2a2c90e7b5..4a146bcf58 100644
--- a/src/window_land.c
+++ b/src/window_land.c
@@ -54,7 +54,7 @@ static void window_land_close();
 static void window_land_mouseup();
 static void window_land_mousedown();
 static void window_land_dropdown();
-static void window_land_update();
+static void window_land_update(rct_window *w);
 static void window_land_invalidate();
 static void window_land_paint();
 
@@ -310,12 +310,8 @@ static void window_land_dropdown()
  *
  *  rct2: 0x00664272
  */
-static void window_land_update()
+static void window_land_update(rct_window *w)
 {
-	rct_window *w;
-
-	__asm mov w, esi
-
 	// Close window if another tool is open
 	if (window_land_should_close())
 		window_close(w);
diff --git a/src/window_map.c b/src/window_map.c
index b7a92563b7..fbb7005077 100644
--- a/src/window_map.c
+++ b/src/window_map.c
@@ -77,7 +77,7 @@ static void window_map_emptysub() { }
 static void window_map_close();
 static void window_map_mouseup();
 static void window_map_mousedown();
-static void window_map_update();
+static void window_map_update(rct_window *w);
 static void window_map_scrollgetsize();
 static void window_map_scrollmousedown();
 static void window_map_invalidate();
@@ -210,7 +210,7 @@ static void window_map_mousedown()
 *
 *  rct2: 0x0068D7FB
 */
-static void window_map_update()
+static void window_map_update(rct_window *w)
 {
 	RCT2_CALLPROC_EBPSAFE(0x0068D7FB);
 }
diff --git a/src/window_news.c b/src/window_news.c
index 4fa036bae0..2bd3134588 100644
--- a/src/window_news.c
+++ b/src/window_news.c
@@ -45,7 +45,7 @@ static rct_widget window_news_widgets[] = {
 
 static void window_news_emptysub() { }
 static void window_news_mouseup();
-static void window_news_update();
+static void window_news_update(rct_window *w);
 static void window_news_scrollgetsize();
 static void window_news_scrollmousedown();
 static void window_news_tooltip();
@@ -140,14 +140,11 @@ static void window_news_mouseup()
  * 
  *  rct2: 0x0066EAB8
  */
-static void window_news_update()
+static void window_news_update(rct_window *w)
 {
 	int i, j, x, y, z;
-	rct_window *w;
 	rct_news_item *newsItems;
 
-	__asm mov w, esi
-
 	if (w->var_480 == -1)
 		return;
 	if (--w->var_484 != 0)
diff --git a/src/window_options.c b/src/window_options.c
index a45f693d6a..49f4285b81 100644
--- a/src/window_options.c
+++ b/src/window_options.c
@@ -105,7 +105,7 @@ static void window_options_emptysub() { }
 static void window_options_mouseup();
 static void window_options_mousedown();
 static void window_options_dropdown();
-static void window_options_update();
+static void window_options_update(rct_window *w);
 static void window_options_paint();
 static void window_options_draw_dropdown_box(w, widget, num_items);
 static void window_options_update_height_markers();
@@ -458,13 +458,13 @@ static void window_options_dropdown()
 *
 *  rct2: 0x006BAD48
 */
-static void window_options_update()
+static void window_options_update(rct_window *w)
 {
-	sint32 format_args = RCT2_GLOBAL(0x009AF280, sint32);
-	rct_window *w;
-	
+	//Has use asm verison incase called by WM_INVALIDATE
 	__asm mov w, esi
 
+	sint32 format_args = RCT2_GLOBAL(0x009AF280, sint32);
+
 	// sound devices
 	if (format_args == -1 || RCT2_GLOBAL(RCT2_ADDRESS_NUM_DSOUND_DEVICES, sint32) == 0) {
 		RCT2_GLOBAL(0x013CE952, uint16) = STR_SOUND_NONE;
diff --git a/src/window_park.c b/src/window_park.c
index 7cddbeca7a..3c05270061 100644
--- a/src/window_park.c
+++ b/src/window_park.c
@@ -218,7 +218,7 @@ static void window_park_entrance_mouseup();
 static void window_park_entrance_resize();
 static void window_park_entrance_mousedown();
 static void window_park_entrance_dropdown();
-static void window_park_entrance_update();
+static void window_park_entrance_update(rct_window *w);
 static void window_park_entrance_toolupdate();
 static void window_park_entrance_tooldown();
 static void window_park_entrance_tooldrag();
@@ -229,38 +229,38 @@ static void window_park_entrance_paint();
 
 static void window_park_rating_mouseup();
 static void window_park_rating_resize();
-static void window_park_rating_update();
+static void window_park_rating_update(rct_window *w);
 static void window_park_rating_invalidate();
 static void window_park_rating_paint();
 
 static void window_park_guests_mouseup();
 static void window_park_guests_resize();
-static void window_park_guests_update();
+static void window_park_guests_update(rct_window *w);
 static void window_park_guests_invalidate();
 static void window_park_guests_paint();
 
 static void window_park_price_mouseup();
 static void window_park_price_resize();
 static void window_park_price_mousedown();
-static void window_park_price_update();
+static void window_park_price_update(rct_window *w);
 static void window_park_price_invalidate();
 static void window_park_price_paint();
 
 static void window_park_stats_mouseup();
 static void window_park_stats_resize();
-static void window_park_stats_update();
+static void window_park_stats_update(rct_window *w);
 static void window_park_stats_invalidate();
 static void window_park_stats_paint();
 
 static void window_park_objective_mouseup();
 static void window_park_objective_resize();
-static void window_park_objective_update();
+static void window_park_objective_update(rct_window *w);
 static void window_park_objective_invalidate();
 static void window_park_objective_paint();
 
 static void window_park_awards_mouseup();
 static void window_park_awards_resize();
-static void window_park_awards_update();
+static void window_park_awards_update(rct_window *w);
 static void window_park_awards_invalidate();
 static void window_park_awards_paint();
 
@@ -773,12 +773,8 @@ static void window_park_entrance_dropdown()
  * 
  *  rct2: 0x006686B5
  */
-static void window_park_entrance_update()
+static void window_park_entrance_update(rct_window *w)
 {
-	rct_window *w;
-
-	__asm mov w, esi
-
 	w->var_48E++;
 	window_invalidate_by_id(w->classification, 1179);
 }
@@ -1146,12 +1142,8 @@ static void window_park_rating_resize()
  *
  *  rct2: 0x00668A21
  */
-static void window_park_rating_update()
+static void window_park_rating_update(rct_window *w)
 {
-	rct_window *w;
-
-	__asm mov w, esi
-
 	w->var_48E++;
 	widget_invalidate(w->classification, w->number, WIDX_TAB_2);
 }
@@ -1288,12 +1280,8 @@ static void window_park_guests_resize()
  *
  *  rct2: 0x00668E06
  */
-static void window_park_guests_update()
+static void window_park_guests_update(rct_window *w)
 {
-	rct_window *w;
-
-	__asm mov w, esi
-
 	w->var_48E++;
 	w->var_492 = (w->var_492 + 1) % 24;
 	widget_invalidate(w->classification, w->number, WIDX_TAB_3);
@@ -1439,12 +1427,8 @@ static void window_park_price_mousedown()
  *
  *  rct2: 0x00669077
  */
-static void window_park_price_update()
+static void window_park_price_update(rct_window *w)
 {
-	rct_window *w;
-
-	__asm mov w, esi
-
 	w->var_48E++;
 	widget_invalidate(w->classification, w->number, WIDX_TAB_4);
 }
@@ -1551,12 +1535,9 @@ static void window_park_stats_resize()
  *
  *  rct2: 0x006692A8
  */
-static void window_park_stats_update()
+static void window_park_stats_update(rct_window *w)
 {
 	int i;
-	rct_window *w;
-
-	__asm mov w, esi
 
 	w->var_48E++;
 	widget_invalidate(w->classification, w->number, WIDX_TAB_5);
@@ -1734,12 +1715,8 @@ static void window_park_objective_resize()
  * 
  *  rct2: 0x0066966C
  */
-static void window_park_objective_update()
+static void window_park_objective_update(rct_window *w)
 {
-	rct_window *w;
-
-	__asm mov w, esi
-
 	w->var_48E++;
 	widget_invalidate(w->classification, w->number, WIDX_TAB_6);
 }
@@ -1887,12 +1864,8 @@ static void window_park_awards_resize()
  *
  *  rct2: 0x0066986D
  */
-static void window_park_awards_update()
+static void window_park_awards_update(rct_window *w)
 {
-	rct_window *w;
-
-	__asm mov w, esi
-
 	w->var_48E++;
 	window_invalidate_by_id(w->classification, 1179);
 }
diff --git a/src/window_ride_list.c b/src/window_ride_list.c
index f7e877ef3d..a7dde38fe8 100644
--- a/src/window_ride_list.c
+++ b/src/window_ride_list.c
@@ -70,7 +70,7 @@ static void window_ride_list_mouseup();
 static void window_ride_list_resize();
 static void window_ride_list_mousedown();
 static void window_ride_list_dropdown();
-static void window_ride_list_update();
+static void window_ride_list_update(rct_window *w);
 static void window_ride_list_scrollgetsize();
 static void window_ride_list_scrollmousedown();
 static void window_ride_list_scrollmouseover();
@@ -297,12 +297,8 @@ static void window_ride_list_dropdown()
  * 
  *  rct2: 0x006B386B
  */
-static void window_ride_list_update()
+static void window_ride_list_update(rct_window *w)
 {
-	rct_window *w;
-
-	__asm mov w, esi
-
 	w->var_48E = (w->var_48E + 1) % 64;
 	widget_invalidate(w->classification, w->number, WIDX_TAB_1 + w->page);
 	if (_window_ride_list_information_type != INFORMATION_TYPE_STATUS)
diff --git a/src/window_tooltip.c b/src/window_tooltip.c
index 95312aea2f..b570a190d3 100644
--- a/src/window_tooltip.c
+++ b/src/window_tooltip.c
@@ -35,7 +35,7 @@ static rct_widget window_tooltip_widgets[] = {
 
 static void window_tooltip_emptysub() { }
 static void window_tooltip_onclose();
-static void window_tooltip_update();
+static void window_tooltip_update(rct_window *w);
 static void window_tooltip_paint();
 
 static void* window_tooltip_events[] = {
@@ -173,7 +173,7 @@ static void window_tooltip_onclose()
  * 
  *  rct2: 0x006EA580
  */
-static void window_tooltip_update()
+static void window_tooltip_update(rct_window *w)
 {
 	if (RCT2_GLOBAL(0x009DE51E, uint8) == 0)
 		RCT2_GLOBAL(RCT2_ADDRESS_TOOLTIP_NOT_SHOWN_TICKS, uint16) = 0;
diff --git a/src/window_water.c b/src/window_water.c
index a58cce6e2f..57c8fc9a09 100644
--- a/src/window_water.c
+++ b/src/window_water.c
@@ -169,12 +169,8 @@ static void window_water_mouseup()
  *
  *  rct2: 0x006E6BCE
  */
-static void window_water_update()
+static void window_water_update(rct_window *w)
 {
-	rct_window *w;
-
-	__asm mov w, esi
-
 	// Close window if another tool is open
 	if (window_water_should_close())
 		window_close(w);