diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 84e8c17d98..894e9b9eb7 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -379,6 +379,8 @@ jobs:
           bundle_name: "groovy"
         - container_image: "debian:buster"
           bundle_name: "buster"
+        - container_image: "debian:bullseye"
+          bundle_name: "bullseye"
 
     runs-on: ubuntu-20.04
     container:
diff --git a/src/3rdparty/squirrel/squirrel/sqstate.cpp b/src/3rdparty/squirrel/squirrel/sqstate.cpp
index eaad6a3f77..8233ad1789 100644
--- a/src/3rdparty/squirrel/squirrel/sqstate.cpp
+++ b/src/3rdparty/squirrel/squirrel/sqstate.cpp
@@ -252,7 +252,7 @@ SQInteger SQSharedState::CollectGarbage(SQVM *vm)
 	SQVM *vms = _thread(_root_vm);
 
 	vms->Mark(&tchain);
-#ifndef NDEBUG
+#ifdef WITH_ASSERT
 	SQInteger x = _table(_thread(_root_vm)->_roottable)->CountUsed();
 #endif
 	_refs_table.Mark(&tchain);
@@ -291,7 +291,7 @@ SQInteger SQSharedState::CollectGarbage(SQVM *vm)
 		t = t->_next;
 	}
 	_gc_chain = tchain;
-#ifndef NDEBUG
+#ifdef WITH_ASSERT
 	SQInteger z = _table(_thread(_root_vm)->_roottable)->CountUsed();
 	assert(z == x);
 #endif
diff --git a/src/3rdparty/squirrel/squirrel/sqvm.cpp b/src/3rdparty/squirrel/squirrel/sqvm.cpp
index 5419c94cf0..ad07ac512d 100644
--- a/src/3rdparty/squirrel/squirrel/sqvm.cpp
+++ b/src/3rdparty/squirrel/squirrel/sqvm.cpp
@@ -1460,7 +1460,7 @@ bool SQVM::DeleteSlot(const SQObjectPtr &self,const SQObjectPtr &key,SQObjectPtr
 			}
 		}
 		res = t;
-				}
+	}
 		break;
 	default:
 		Raise_Error("attempt to delete a slot from a %s",GetTypeName(self));
@@ -1471,7 +1471,7 @@ bool SQVM::DeleteSlot(const SQObjectPtr &self,const SQObjectPtr &key,SQObjectPtr
 
 bool SQVM::Call(SQObjectPtr &closure,SQInteger nparams,SQInteger stackbase,SQObjectPtr &outres,SQBool raiseerror,SQBool can_suspend)
 {
-#ifndef NDEBUG
+#ifdef WITH_ASSERT
 	SQInteger prevstackbase = _stackbase;
 #endif
 	switch(type(closure)) {
@@ -1482,13 +1482,13 @@ bool SQVM::Call(SQObjectPtr &closure,SQInteger nparams,SQInteger stackbase,SQObj
 		bool ret = Execute(closure, _top - nparams, nparams, stackbase,outres,raiseerror);
 		this->_can_suspend = backup_suspend;
 		return ret;
-					 }
+	}
 		break;
-	case OT_NATIVECLOSURE:{
+	case OT_NATIVECLOSURE: {
 		bool suspend;
 		return CallNative(_nativeclosure(closure), nparams, stackbase, outres,suspend);
 
-						  }
+	}
 		break;
 	case OT_CLASS: {
 		SQObjectPtr constr;
@@ -1499,12 +1499,12 @@ bool SQVM::Call(SQObjectPtr &closure,SQInteger nparams,SQInteger stackbase,SQObj
 			return Call(constr,nparams,stackbase,temp,raiseerror,false);
 		}
 		return true;
-				   }
+	}
 		break;
 	default:
 		return false;
 	}
-#ifndef NDEBUG
+#ifdef WITH_ASSERT
 	if(!_suspended) {
 		assert(_stackbase == prevstackbase);
 	}
diff --git a/src/core/pool_type.hpp b/src/core/pool_type.hpp
index e847dfbb72..33f952dde4 100644
--- a/src/core/pool_type.hpp
+++ b/src/core/pool_type.hpp
@@ -82,7 +82,7 @@ struct Pool : PoolBase {
 	/* Ensure Tmax_size is within the bounds of Tindex. */
 	static_assert((uint64)(Tmax_size - 1) >> 8 * sizeof(Tindex) == 0);
 
-	static const size_t MAX_SIZE = Tmax_size; ///< Make template parameter accessible from outside
+	static constexpr size_t MAX_SIZE = Tmax_size; ///< Make template parameter accessible from outside
 
 	const char * const name; ///< Name of this pool
 
diff --git a/src/fileio.cpp b/src/fileio.cpp
index 9a9e7e05dc..6b33f8aa24 100644
--- a/src/fileio.cpp
+++ b/src/fileio.cpp
@@ -1259,7 +1259,7 @@ void SanitizeFilename(char *filename)
  * @return Pointer to new memory containing the loaded data, or \c nullptr if loading failed.
  * @note If \a maxsize less than the length of the file, loading fails.
  */
-std::unique_ptr<char> ReadFileToMem(const std::string &filename, size_t &lenp, size_t maxsize)
+std::unique_ptr<char[]> ReadFileToMem(const std::string &filename, size_t &lenp, size_t maxsize)
 {
 	FILE *in = fopen(filename.c_str(), "rb");
 	if (in == nullptr) return nullptr;
@@ -1271,10 +1271,7 @@ std::unique_ptr<char> ReadFileToMem(const std::string &filename, size_t &lenp, s
 	fseek(in, 0, SEEK_SET);
 	if (len > maxsize) return nullptr;
 
-	/* std::unique_ptr assumes new/delete unless a custom deleter is supplied.
-	 * As we don't want to have to carry that deleter all over the place, use
-	 * new directly to allocate the memory instead of malloc. */
-	std::unique_ptr<char> mem(static_cast<char *>(::operator new(len + 1)));
+	std::unique_ptr<char[]> mem = std::make_unique<char[]>(len + 1);
 
 	mem.get()[len] = 0;
 	if (fread(mem.get(), len, 1, in) != 1) return nullptr;
diff --git a/src/fileio_func.h b/src/fileio_func.h
index f373188fa8..6dbaea8970 100644
--- a/src/fileio_func.h
+++ b/src/fileio_func.h
@@ -49,7 +49,7 @@ const char *FiosGetScreenshotDir();
 void SanitizeFilename(char *filename);
 void AppendPathSeparator(std::string &buf);
 void DeterminePaths(const char *exe);
-std::unique_ptr<char> ReadFileToMem(const std::string &filename, size_t &lenp, size_t maxsize);
+std::unique_ptr<char[]> ReadFileToMem(const std::string &filename, size_t &lenp, size_t maxsize);
 bool FileExists(const std::string &filename);
 bool ExtractTar(const std::string &tar_filename, Subdirectory subdir);
 
diff --git a/src/lang/catalan.txt b/src/lang/catalan.txt
index 11fc4f4a91..3b9df8b37f 100644
--- a/src/lang/catalan.txt
+++ b/src/lang/catalan.txt
@@ -2689,7 +2689,7 @@ STR_LAND_AREA_INFORMATION_OWNER                                 :{BLACK}Propieta
 STR_LAND_AREA_INFORMATION_ROAD_OWNER                            :{BLACK}Propietari de la carretera: {LTBLUE}{STRING}
 STR_LAND_AREA_INFORMATION_TRAM_OWNER                            :{BLACK}Propietari del rail del tramvia: {LTBLUE}{STRING}
 STR_LAND_AREA_INFORMATION_RAIL_OWNER                            :{BLACK}Propietari del rail: {LTBLUE}{STRING}
-STR_LAND_AREA_INFORMATION_LOCAL_AUTHORITY                       :{BLACK}Autoritat Local: {LTBLUE}{STRING}
+STR_LAND_AREA_INFORMATION_LOCAL_AUTHORITY                       :{BLACK}Autoritat local: {LTBLUE}{STRING}
 STR_LAND_AREA_INFORMATION_LOCAL_AUTHORITY_NONE                  :Cap
 STR_LAND_AREA_INFORMATION_LANDINFO_COORDS                       :{BLACK}Coordenades: {LTBLUE}{NUM} x {NUM} x {NUM} ({STRING})
 STR_LAND_AREA_INFORMATION_BUILD_DATE                            :{BLACK}Construït: {LTBLUE}{DATE_LONG}
diff --git a/src/lang/spanish.txt b/src/lang/spanish.txt
index 778b1b9eab..847986a93a 100644
--- a/src/lang/spanish.txt
+++ b/src/lang/spanish.txt
@@ -1087,11 +1087,11 @@ STR_NUM_CUSTOM                                                  :Personalizado
 STR_NUM_CUSTOM_NUMBER                                           :Personalizado ({NUM})
 
 STR_VARIETY_NONE                                                :Ninguna
-STR_VARIETY_VERY_LOW                                            :Muy baja
+STR_VARIETY_VERY_LOW                                            :Muy Baja
 STR_VARIETY_LOW                                                 :Baja
 STR_VARIETY_MEDIUM                                              :Media
 STR_VARIETY_HIGH                                                :Alta
-STR_VARIETY_VERY_HIGH                                           :Muy alta
+STR_VARIETY_VERY_HIGH                                           :Muy Alta
 
 STR_AI_SPEED_VERY_SLOW                                          :Muy lenta
 STR_AI_SPEED_SLOW                                               :Lenta
@@ -1099,7 +1099,7 @@ STR_AI_SPEED_MEDIUM                                             :Media
 STR_AI_SPEED_FAST                                               :Rápida
 STR_AI_SPEED_VERY_FAST                                          :Muy rápida
 
-STR_SEA_LEVEL_VERY_LOW                                          :Muy bajo
+STR_SEA_LEVEL_VERY_LOW                                          :Muy Bajo
 STR_SEA_LEVEL_LOW                                               :Bajo
 STR_SEA_LEVEL_MEDIUM                                            :Medio
 STR_SEA_LEVEL_HIGH                                              :Alto
diff --git a/src/object.h b/src/object.h
index e3f0c84ff5..c374ba9501 100644
--- a/src/object.h
+++ b/src/object.h
@@ -18,6 +18,6 @@ void UpdateCompanyHQ(TileIndex tile, uint score);
 
 void BuildObject(ObjectType type, TileIndex tile, CompanyID owner = OWNER_NONE, struct Town *town = nullptr, uint8 view = 0);
 
-void ShowBuildObjectPicker();
+Window *ShowBuildObjectPicker();
 
 #endif /* OBJECT_H */
diff --git a/src/object_gui.cpp b/src/object_gui.cpp
index 7a6edb97d4..4ee3b7265f 100644
--- a/src/object_gui.cpp
+++ b/src/object_gui.cpp
@@ -9,9 +9,11 @@
 
 #include "stdafx.h"
 #include "command_func.h"
+#include "hotkeys.h"
 #include "newgrf.h"
 #include "newgrf_object.h"
 #include "newgrf_text.h"
+#include "object.h"
 #include "querystring_gui.h"
 #include "sortlist_type.h"
 #include "stringfilter_type.h"
@@ -33,6 +35,11 @@ static ObjectClassID _selected_object_class; ///< Currently selected available o
 static int _selected_object_index;           ///< Index of the currently selected object if existing, else \c -1.
 static uint8 _selected_object_view;          ///< the view of the selected object
 
+/** Enum referring to the Hotkeys in the build object window */
+enum BuildObjectHotkeys {
+	BOHK_FOCUS_FILTER_BOX, ///< Focus the edit box for editing the filter string
+};
+
 /** The window used for building objects. */
 class BuildObjectWindow : public Window {
 	typedef GUIList<ObjectClassID, StringFilter &> GUIObjectClassList; ///< Type definition for the list to hold available object classes.
@@ -88,7 +95,7 @@ class BuildObjectWindow : public Window {
 	}
 
 public:
-	BuildObjectWindow(WindowDesc *desc, WindowNumber number) : Window(desc), info_height(1), filter_editbox(EDITBOX_MAX_SIZE)
+	BuildObjectWindow(WindowDesc *desc, WindowNumber number) : Window(desc), info_height(1), filter_editbox(EDITBOX_MAX_SIZE * MAX_CHAR_LENGTH, EDITBOX_MAX_SIZE)
 	{
 		this->CreateNestedTree();
 
@@ -544,6 +551,21 @@ public:
 		this->UpdateButtons(_selected_object_class, -1, _selected_object_view);
 	}
 
+	EventState OnHotkey(int hotkey) override
+	{
+		switch (hotkey) {
+			case BOHK_FOCUS_FILTER_BOX:
+				this->SetFocusedWidget(WID_BO_FILTER);
+				SetFocusedWindow(this); // The user has asked to give focus to the text box, so make sure this window is focused.
+				break;
+
+			default:
+				return ES_NOT_HANDLED;
+		}
+
+		return ES_HANDLED;
+	}
+
 	void OnEditboxChanged(int wid) override
 	{
 		string_filter.SetFilterTerm(this->filter_editbox.text.buf);
@@ -597,8 +619,29 @@ public:
 		}
 		this->SelectOtherObject(-1);
 	}
+
+	static HotkeyList hotkeys;
 };
 
+/**
+ * Handler for global hotkeys of the BuildObjectWindow.
+ * @param hotkey Hotkey
+ * @return ES_HANDLED if hotkey was accepted.
+ */
+static EventState BuildObjectGlobalHotkeys(int hotkey)
+{
+	if (_game_mode == GM_MENU) return ES_NOT_HANDLED;
+	Window *w = ShowBuildObjectPicker();
+	if (w == nullptr) return ES_NOT_HANDLED;
+	return w->OnHotkey(hotkey);
+}
+
+static Hotkey buildobject_hotkeys[] = {
+	Hotkey('F', "focus_filter_box", BOHK_FOCUS_FILTER_BOX),
+	HOTKEY_LIST_END
+};
+HotkeyList BuildObjectWindow::hotkeys("buildobject", buildobject_hotkeys, BuildObjectGlobalHotkeys);
+
 Listing BuildObjectWindow::last_sorting = { false, 0 };
 Filtering BuildObjectWindow::last_filtering = { false, 0 };
 
@@ -661,16 +704,18 @@ static WindowDesc _build_object_desc(
 	WDP_AUTO, "build_object", 0, 0,
 	WC_BUILD_OBJECT, WC_BUILD_TOOLBAR,
 	WDF_CONSTRUCTION,
-	_nested_build_object_widgets, lengthof(_nested_build_object_widgets)
+	_nested_build_object_widgets, lengthof(_nested_build_object_widgets),
+	&BuildObjectWindow::hotkeys
 );
 
 /** Show our object picker.  */
-void ShowBuildObjectPicker()
+Window *ShowBuildObjectPicker()
 {
 	/* Don't show the place object button when there are no objects to place. */
 	if (ObjectClass::GetUIClassCount() > 0) {
-		AllocateWindowDescFront<BuildObjectWindow>(&_build_object_desc, 0);
+		return AllocateWindowDescFront<BuildObjectWindow>(&_build_object_desc, 0);
 	}
+	return nullptr;
 }
 
 /** Reset all data of the object GUI. */
diff --git a/src/rail_gui.cpp b/src/rail_gui.cpp
index 6e7c825a01..da9e726edc 100644
--- a/src/rail_gui.cpp
+++ b/src/rail_gui.cpp
@@ -72,7 +72,7 @@ static RailStationGUISettings _railstation; ///< Settings of the station builder
 static void HandleStationPlacement(TileIndex start, TileIndex end);
 static void ShowBuildTrainDepotPicker(Window *parent);
 static void ShowBuildWaypointPicker(Window *parent);
-static void ShowStationBuilder(Window *parent);
+static Window *ShowStationBuilder(Window *parent);
 static void ShowSignalBuilder(Window *parent);
 
 /**
@@ -934,6 +934,11 @@ static void HandleStationPlacement(TileIndex start, TileIndex end)
 	ShowSelectStationIfNeeded(cmdcont, ta);
 }
 
+/** Enum referring to the Hotkeys in the build rail station window */
+enum BuildRalStationHotkeys {
+	BRASHK_FOCUS_FILTER_BOX, ///< Focus the edit box for editing the filter string
+};
+
 struct BuildRailStationWindow : public PickerWindowBase {
 private:
 	uint line_height;     ///< Height of a single line in the newstation selection matrix (#WID_BRAS_NEWST_LIST widget).
@@ -1005,7 +1010,7 @@ private:
 	}
 
 public:
-	BuildRailStationWindow(WindowDesc *desc, Window *parent, bool newstation) : PickerWindowBase(desc, parent), filter_editbox(EDITBOX_MAX_SIZE)
+	BuildRailStationWindow(WindowDesc *desc, Window *parent, bool newstation) : PickerWindowBase(desc, parent), filter_editbox(EDITBOX_MAX_SIZE * MAX_CHAR_LENGTH, EDITBOX_MAX_SIZE)
 	{
 		this->coverage_height = 2 * FONT_HEIGHT_NORMAL + 3 * WD_PAR_VSEP_NORMAL;
 		this->vscroll = nullptr;
@@ -1159,6 +1164,21 @@ public:
 		this->BuildStationClassesAvailable();
 	}
 
+	EventState OnHotkey(int hotkey) override
+	{
+		switch (hotkey) {
+			case BRASHK_FOCUS_FILTER_BOX:
+				this->SetFocusedWidget(WID_BRAS_FILTER_EDITBOX);
+				SetFocusedWindow(this); // The user has asked to give focus to the text box, so make sure this window is focused.
+				break;
+
+			default:
+				return ES_NOT_HANDLED;
+		}
+
+		return ES_HANDLED;
+	}
+
 	void OnEditboxChanged(int wid) override
 	{
 		string_filter.SetFilterTerm(this->filter_editbox.text.buf);
@@ -1545,8 +1565,29 @@ public:
 	{
 		CheckRedrawStationCoverage(this);
 	}
+
+	static HotkeyList hotkeys;
 };
 
+/**
+ * Handler for global hotkeys of the BuildRailStationWindow.
+ * @param hotkey Hotkey
+ * @return ES_HANDLED if hotkey was accepted.
+ */
+static EventState BuildRailStationGlobalHotkeys(int hotkey)
+{
+	if (_game_mode == GM_MENU) return ES_NOT_HANDLED;
+	Window *w = ShowStationBuilder(FindWindowById(WC_BUILD_TOOLBAR, TRANSPORT_RAIL));
+	if (w == nullptr) return ES_NOT_HANDLED;
+	return w->OnHotkey(hotkey);
+}
+
+static Hotkey buildrailstation_hotkeys[] = {
+	Hotkey('F', "focus_filter_box", BRASHK_FOCUS_FILTER_BOX),
+	HOTKEY_LIST_END
+};
+HotkeyList BuildRailStationWindow::hotkeys("buildrailstation", buildrailstation_hotkeys, BuildRailStationGlobalHotkeys);
+
 Listing BuildRailStationWindow::last_sorting = { false, 0 };
 Filtering BuildRailStationWindow::last_filtering = { false, 0 };
 
@@ -1679,14 +1720,15 @@ static WindowDesc _station_builder_desc(
 	WDP_AUTO, "build_station_rail", 0, 0,
 	WC_BUILD_STATION, WC_BUILD_TOOLBAR,
 	WDF_CONSTRUCTION,
-	_nested_station_builder_widgets, lengthof(_nested_station_builder_widgets)
+	_nested_station_builder_widgets, lengthof(_nested_station_builder_widgets),
+	&BuildRailStationWindow::hotkeys
 );
 
 /** Open station build window */
-static void ShowStationBuilder(Window *parent)
+static Window *ShowStationBuilder(Window *parent)
 {
 	bool newstations = StationClass::GetClassCount() > 2 || StationClass::Get(STAT_CLASS_DFLT)->GetSpecCount() != 1;
-	new BuildRailStationWindow(&_station_builder_desc, parent, newstations);
+	return new BuildRailStationWindow(&_station_builder_desc, parent, newstations);
 }
 
 struct BuildSignalWindow : public PickerWindowBase {
diff --git a/src/spritecache.cpp b/src/spritecache.cpp
index 0426e297b1..4cb99bab75 100644
--- a/src/spritecache.cpp
+++ b/src/spritecache.cpp
@@ -229,7 +229,7 @@ static void ResizeSpriteOut(SpriteLoader::Sprite *sprite, ZoomLevel zoom)
 
 	SpriteLoader::CommonPixel *dst = sprite[zoom].data;
 	const SpriteLoader::CommonPixel *src = sprite[zoom - 1].data;
-#ifndef NDEBUG
+#ifdef WITH_ASSERT
 	const SpriteLoader::CommonPixel *src_end = src + sprite[zoom - 1].height * sprite[zoom - 1].width;
 #endif
 
diff --git a/src/strings.cpp b/src/strings.cpp
index 2c3933a120..e28943c57a 100644
--- a/src/strings.cpp
+++ b/src/strings.cpp
@@ -185,8 +185,16 @@ struct LanguagePack : public LanguagePackHeader {
 	char data[]; // list of strings
 };
 
+struct LanguagePackDeleter {
+	void operator()(LanguagePack *langpack)
+	{
+		/* LanguagePack is in fact reinterpreted char[], we need to reinterpret it back to free it properly. */
+		delete[] reinterpret_cast<char*>(langpack);
+	}
+};
+
 struct LoadedLanguagePack {
-	std::unique_ptr<LanguagePack> langpack;
+	std::unique_ptr<LanguagePack, LanguagePackDeleter> langpack;
 
 	std::vector<char *> offsets;
 
@@ -1713,7 +1721,7 @@ bool ReadLanguagePack(const LanguageMetadata *lang)
 {
 	/* Current language pack */
 	size_t len = 0;
-	std::unique_ptr<LanguagePack> lang_pack(reinterpret_cast<LanguagePack *>(ReadFileToMem(lang->file, len, 1U << 20).release()));
+	std::unique_ptr<LanguagePack, LanguagePackDeleter> lang_pack(reinterpret_cast<LanguagePack *>(ReadFileToMem(lang->file, len, 1U << 20).release()));
 	if (!lang_pack) return false;
 
 	/* End of read data (+ terminating zero added in ReadFileToMem()) */
diff --git a/src/tgp.cpp b/src/tgp.cpp
index 39fda6e6b3..e23b2643df 100644
--- a/src/tgp.cpp
+++ b/src/tgp.cpp
@@ -658,7 +658,7 @@ static void HeightMapCurves(uint level)
 			for (uint t = 0; t < lengthof(curve_maps); t++) {
 				if (!HasBit(corner_bits, t)) continue;
 
-#ifndef NDEBUG
+#ifdef WITH_ASSERT
 				bool found = false;
 #endif
 				const control_point_t *cm = curve_maps[t].list;
@@ -668,7 +668,7 @@ static void HeightMapCurves(uint level)
 
 					if (*h >= p1.x && *h < p2.x) {
 						ht[t] = p1.y + (*h - p1.x) * (p2.y - p1.y) / (p2.x - p1.x);
-#ifndef NDEBUG
+#ifdef WITH_ASSERT
 						found = true;
 #endif
 						break;
diff --git a/src/town_cmd.cpp b/src/town_cmd.cpp
index 023063c1f0..43f3523f8e 100644
--- a/src/town_cmd.cpp
+++ b/src/town_cmd.cpp
@@ -107,7 +107,7 @@ Town::~Town()
 	DeleteWindowById(WC_TOWN_VIEW, this->index);
 
 	/* Check no industry is related to us. */
-#ifndef NDEBUG
+#ifdef WITH_ASSERT
 	for (const Industry *i : Industry::Iterate()) assert(i->town != this);
 
 	/* ... and no object is related to us. */
diff --git a/src/townname.cpp b/src/townname.cpp
index 082c40f75e..519391f14e 100644
--- a/src/townname.cpp
+++ b/src/townname.cpp
@@ -600,7 +600,7 @@ static char *MakeCzechTownName(char *buf, const char *last, uint32 seed)
 		return strecpy(buf, _name_czech_real[SeedModChance(4, lengthof(_name_czech_real), seed)], last);
 	}
 
-#ifndef NDEBUG
+#ifdef WITH_ASSERT
 	const char *orig = buf;
 #endif
 
diff --git a/src/vehicle.cpp b/src/vehicle.cpp
index 8ffaea4082..a9af24c55a 100644
--- a/src/vehicle.cpp
+++ b/src/vehicle.cpp
@@ -953,7 +953,7 @@ void CallVehicleTicks()
 	PerformanceAccumulator::Reset(PFE_GL_AIRCRAFT);
 
 	for (Vehicle *v : Vehicle::Iterate()) {
-#ifndef NDEBUG
+#ifdef WITH_ASSERT
 		size_t vehicle_index = v->index;
 #endif
 
diff --git a/src/widget.cpp b/src/widget.cpp
index b656098fab..45a7232577 100644
--- a/src/widget.cpp
+++ b/src/widget.cpp
@@ -1390,7 +1390,7 @@ void NWidgetHorizontal::SetupSmallestSize(Window *w, bool init_array)
 		this->smallest_y = std::max(this->smallest_y, child_wid->smallest_y + child_wid->padding_top + child_wid->padding_bottom);
 	}
 	/* 1b. Make the container higher if needed to accommodate all children nicely. */
-#ifndef NDEBUG
+#ifdef WITH_ASSERT
 	uint max_smallest = this->smallest_y + 3 * max_vert_fill; // Upper limit to computing smallest height.
 #endif
 	uint cur_height = this->smallest_y;
@@ -1557,7 +1557,7 @@ void NWidgetVertical::SetupSmallestSize(Window *w, bool init_array)
 		this->smallest_x = std::max(this->smallest_x, child_wid->smallest_x + child_wid->padding_left + child_wid->padding_right);
 	}
 	/* 1b. Make the container wider if needed to accommodate all children nicely. */
-#ifndef NDEBUG
+#ifdef WITH_ASSERT
 	uint max_smallest = this->smallest_x + 3 * max_hor_fill; // Upper limit to computing smallest height.
 #endif
 	uint cur_width = this->smallest_x;