diff --git a/src/cheat_gui.cpp b/src/cheat_gui.cpp
--- a/src/cheat_gui.cpp
+++ b/src/cheat_gui.cpp
@@ -104,7 +104,7 @@ static int32 ClickChangeDateCheat(int32 
 
 	SetDate(ConvertYMDToDate(_cur_year + p2, ymd.month, ymd.day));
 	EnginesMonthlyLoop();
-	SetWindowDirty(FindWindowById(WC_STATUS_BAR, 0));
+	InvalidateWindow(WC_STATUS_BAR, 0);
 	InvalidateWindowClassesData(WC_BUILD_STATION, 0);
 	ResetSignalVariant();
 	return _cur_year;
diff --git a/src/console_gui.cpp b/src/console_gui.cpp
--- a/src/console_gui.cpp
+++ b/src/console_gui.cpp
@@ -141,7 +141,7 @@ static void IConsoleClearCommand()
 	_iconsole_cmdline.width = 0;
 	_iconsole_cmdline.caretpos = 0;
 	_iconsole_cmdline.caretxoffs = 0;
-	SetWindowDirty(FindWindowById(WC_CONSOLE, 0));
+	InvalidateWindow(WC_CONSOLE, 0);
 }
 
 static inline void IConsoleResetHistoryPos() {_iconsole_historypos = ICON_HISTORY_SIZE - 1;}
@@ -470,5 +470,5 @@ static void IConsoleHistoryNavigate(int 
 void IConsoleGUIPrint(ConsoleColour colour_code, char *str)
 {
 	new IConsoleLine(str, (TextColour)colour_code);
-	SetWindowDirty(FindWindowById(WC_CONSOLE, 0));
+	InvalidateWindow(WC_CONSOLE, 0);
 }
diff --git a/src/misc_gui.cpp b/src/misc_gui.cpp
--- a/src/misc_gui.cpp
+++ b/src/misc_gui.cpp
@@ -929,7 +929,7 @@ void CheckRedrawStationCoverage(const Wi
 {
 	if (_thd.dirty & 1) {
 		_thd.dirty &= ~1;
-		SetWindowDirty(w);
+		w->SetDirty();
 	}
 }
 
@@ -2079,7 +2079,7 @@ void ShowSaveLoadDialog(SaveLoadDialogMo
 
 void RedrawAutosave()
 {
-	SetWindowDirty(FindWindowById(WC_STATUS_BAR, 0));
+	InvalidateWindow(WC_STATUS_BAR, 0);
 }
 
 void SetFiosType(const byte fiostype)
diff --git a/src/rail_gui.cpp b/src/rail_gui.cpp
--- a/src/rail_gui.cpp
+++ b/src/rail_gui.cpp
@@ -1601,14 +1601,14 @@ public:
 			case BSW_DRAG_SIGNALS_DENSITY_DECREASE:
 				if (_settings_client.gui.drag_signals_density > 1) {
 					_settings_client.gui.drag_signals_density--;
-					SetWindowDirty(FindWindowById(WC_GAME_OPTIONS, 0));
+					InvalidateWindow(WC_GAME_OPTIONS, 0);
 				}
 				break;
 
 			case BSW_DRAG_SIGNALS_DENSITY_INCREASE:
 				if (_settings_client.gui.drag_signals_density < 20) {
 					_settings_client.gui.drag_signals_density++;
-					SetWindowDirty(FindWindowById(WC_GAME_OPTIONS, 0));
+					InvalidateWindow(WC_GAME_OPTIONS, 0);
 				}
 				break;
 
diff --git a/src/settings.cpp b/src/settings.cpp
--- a/src/settings.cpp
+++ b/src/settings.cpp
@@ -752,7 +752,7 @@ static bool TrainAccelerationModelChange
 
 static bool DragSignalsDensityChanged(int32)
 {
-	SetWindowDirty(FindWindowById(WC_BUILD_SIGNAL, 0));
+	InvalidateWindow(WC_BUILD_SIGNAL, 0);
 
 	return true;
 }
diff --git a/src/toolbar_gui.cpp b/src/toolbar_gui.cpp
--- a/src/toolbar_gui.cpp
+++ b/src/toolbar_gui.cpp
@@ -782,7 +782,7 @@ static void ToolbarSwitchClick(Window *w
 
 	SplitToolbar(w);
 	w->HandleButtonClick(TBN_SWITCHBAR);
-	SetWindowDirty(w);
+	w->SetDirty();
 	SndPlayFx(SND_15_BEEP);
 }
 
diff --git a/src/window.cpp b/src/window.cpp
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -591,16 +591,6 @@ void Window::SetDirty() const
 	SetDirtyBlocks(this->left, this->top, this->left + this->width, this->top + this->height);
 }
 
-/**
- * Mark entire window as dirty (in need of re-paint)
- * @param w Window to redraw
- * @ingroup dirty
- */
-void SetWindowDirty(const Window *w)
-{
-	if (w != NULL) w->SetDirty();
-}
-
 /** Re-initialize a window. */
 void Window::ReInit()
 {
diff --git a/src/window_func.h b/src/window_func.h
--- a/src/window_func.h
+++ b/src/window_func.h
@@ -15,8 +15,6 @@
 #include "window_type.h"
 #include "company_type.h"
 
-void SetWindowDirty(const Window *w);
-
 Window *FindWindowById(WindowClass cls, WindowNumber number);
 void ChangeWindowOwner(Owner old_owner, Owner new_owner);