diff --git a/src/common/audio/sound/s_reverbedit.cpp b/src/common/audio/sound/s_reverbedit.cpp
index 54e0a3431..25993a400 100644
--- a/src/common/audio/sound/s_reverbedit.cpp
+++ b/src/common/audio/sound/s_reverbedit.cpp
@@ -39,9 +39,8 @@
 #include "templates.h"
 #include "filesystem.h"
 #include "i_system.h"
-#include "m_misc.h"
 #include "printf.h"
-
+#include "i_specialpaths.h"
 #include "c_cvars.h"
 #include "c_dispatch.h"
 #include "vm.h"
diff --git a/src/common/objects/dobjtype.cpp b/src/common/objects/dobjtype.cpp
index 83653c20e..cf6d32d04 100644
--- a/src/common/objects/dobjtype.cpp
+++ b/src/common/objects/dobjtype.cpp
@@ -922,3 +922,31 @@ unsigned GetVirtualIndex(PClass *cls, const char *funcname)
 	return VIndex;
 }
 
+
+void PClass::InitializeDefaults()
+{
+	if (VMType != nullptr)	// purely internal classes have no symbol table
+	{
+		if (bRuntimeClass)
+		{
+			// Copy parent values from the parent defaults.
+			assert(ParentClass != nullptr);
+			if (Defaults != nullptr) ParentClass->InitializeSpecials(Defaults, ParentClass->Defaults, &PClass::SpecialInits);
+			for (const PField* field : Fields)
+			{
+				if (!(field->Flags & VARF_Native) && !(field->Flags & VARF_Meta))
+				{
+					field->Type->SetDefaultValue(Defaults, unsigned(field->Offset), &SpecialInits);
+				}
+			}
+		}
+		if (Meta != nullptr) ParentClass->InitializeSpecials(Meta, ParentClass->Meta, &PClass::MetaInits);
+		for (const PField* field : Fields)
+		{
+			if (!(field->Flags & VARF_Native) && (field->Flags & VARF_Meta))
+			{
+				field->Type->SetDefaultValue(Meta, unsigned(field->Offset), &MetaInits);
+			}
+		}
+	}
+}
\ No newline at end of file
diff --git a/src/common/objects/dobjtype.h b/src/common/objects/dobjtype.h
index 16adbf72f..07a48454e 100644
--- a/src/common/objects/dobjtype.h
+++ b/src/common/objects/dobjtype.h
@@ -46,6 +46,7 @@ public:
 	int FindVirtualIndex(FName name, PFunction::Variant *variant, PFunction *parentfunc);
 	PSymbol *FindSymbol(FName symname, bool searchparents) const;
 	PField *AddField(FName name, PType *type, uint32_t flags);
+	void InitializeDefaults();
 
 	static void StaticInit();
 	static void StaticShutdown();
diff --git a/src/common/scripting/frontend/zcc_compile.cpp b/src/common/scripting/frontend/zcc_compile.cpp
index 59870ee9b..5c73fc1cc 100644
--- a/src/common/scripting/frontend/zcc_compile.cpp
+++ b/src/common/scripting/frontend/zcc_compile.cpp
@@ -650,6 +650,7 @@ int ZCCCompiler::Compile()
 	CreateStructTypes();
 	CompileAllConstants();
 	CompileAllFields();
+	InitDefaults();
 	InitFunctions();
 	return FScriptPosition::ErrorCounter;
 }
@@ -1942,6 +1943,18 @@ void ZCCCompiler::SetImplicitArgs(TArray<PType*>* args, TArray<uint32_t>* argfla
 }
 
 
+void ZCCCompiler::InitDefaults()
+{
+	for (auto c : Classes)
+	{
+		if (c->ClassType()->ParentClass)
+		{
+			auto ti = c->ClassType();
+			ti->InitializeDefaults();
+		}
+	}
+}
+
 //==========================================================================
 //
 //
diff --git a/src/common/scripting/frontend/zcc_compile.h b/src/common/scripting/frontend/zcc_compile.h
index 5c90f77dd..ca19d8aff 100644
--- a/src/common/scripting/frontend/zcc_compile.h
+++ b/src/common/scripting/frontend/zcc_compile.h
@@ -139,6 +139,7 @@ protected:
 	void CompileFunction(ZCC_StructWork *c, ZCC_FuncDeclarator *f, bool forclass);
 
 	void InitFunctions();
+	virtual void InitDefaults();
 	
 	TArray<ZCC_ConstantDef *> Constants;
 	TArray<ZCC_StructWork *> Structs;
diff --git a/src/common/scripting/interface/vmnatives.cpp b/src/common/scripting/interface/vmnatives.cpp
index 03348124a..b62e22993 100644
--- a/src/common/scripting/interface/vmnatives.cpp
+++ b/src/common/scripting/interface/vmnatives.cpp
@@ -46,6 +46,7 @@
 #include "vm.h"
 #include "gstrings.h"
 #include "printf.h"
+#include "s_music.h"
 
 
 //==========================================================================
@@ -75,6 +76,20 @@ DEFINE_ACTION_FUNCTION(_TexMan, GetName)
 	ACTION_RETURN_STRING(retval);
 }
 
+static int CheckForTexture(const FString& name, int type, int flags)
+{
+	return TexMan.CheckForTexture(name, static_cast<ETextureType>(type), flags).GetIndex();
+}
+
+DEFINE_ACTION_FUNCTION_NATIVE(_TexMan, CheckForTexture, CheckForTexture)
+{
+	PARAM_PROLOGUE;
+	PARAM_STRING(name);
+	PARAM_INT(type);
+	PARAM_INT(flags);
+	ACTION_RETURN_INT(CheckForTexture(name, type, flags));
+}
+
 //==========================================================================
 //
 //
@@ -618,3 +633,11 @@ DEFINE_ACTION_FUNCTION(_Console, Printf)
 	Printf("%s\n", s.GetChars());
 	return 0;
 }
+
+DEFINE_GLOBAL_NAMED(mus_playing, musplaying);
+DEFINE_FIELD_X(MusPlayingInfo, MusPlayingInfo, name);
+DEFINE_FIELD_X(MusPlayingInfo, MusPlayingInfo, baseorder);
+DEFINE_FIELD_X(MusPlayingInfo, MusPlayingInfo, loop);
+
+DEFINE_GLOBAL_NAMED(PClass::AllClasses, AllClasses)
+DEFINE_GLOBAL(Bindings)
diff --git a/src/common/scripting/vm/vmexec.h b/src/common/scripting/vm/vmexec.h
index d88945a44..154cac29e 100644
--- a/src/common/scripting/vm/vmexec.h
+++ b/src/common/scripting/vm/vmexec.h
@@ -360,6 +360,10 @@ static int ExecScriptFunc(VMFrameStack *stack, VMReturn *ret, int numret)
 	OP(SS):
 		ASSERTA(a); ASSERTS(B); ASSERTKD(C);
 		GETADDR(PA,KC,X_WRITE_NIL);
+#ifdef _DEBUG
+		// Should never happen, if it does it indicates a compiler side problem.
+		if (((FString*)ptr)->GetChars() == nullptr) ThrowAbortException(X_OTHER, "Uninitialized string");
+#endif
 		*(FString *)ptr = reg.s[B];
 		NEXTOP;
 	OP(SS_R):
diff --git a/src/d_gui.h b/src/d_gui.h
deleted file mode 100644
index 774f928ac..000000000
--- a/src/d_gui.h
+++ /dev/null
@@ -1,115 +0,0 @@
-/*
-** d_gui.h
-**
-**---------------------------------------------------------------------------
-** Copyright 1998-2006 Randy Heit
-** All rights reserved.
-**
-** Redistribution and use in source and binary forms, with or without
-** modification, are permitted provided that the following conditions
-** are met:
-**
-** 1. Redistributions of source code must retain the above copyright
-**    notice, this list of conditions and the following disclaimer.
-** 2. Redistributions in binary form must reproduce the above copyright
-**    notice, this list of conditions and the following disclaimer in the
-**    documentation and/or other materials provided with the distribution.
-** 3. The name of the author may not be used to endorse or promote products
-**    derived from this software without specific prior written permission.
-**
-** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
-** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
-** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
-** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
-** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
-** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
-** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-**---------------------------------------------------------------------------
-**
-** So when do I get a real UT-like windowing system?
-*/
-
-#ifndef __D_GUI_H__
-#define __D_GUI_H__
-
-// For a GUIEvent, x and y specify absolute location of mouse pointer
-enum EGUIEvent
-{
-	EV_GUI_None,
-	EV_GUI_KeyDown,			// data1: unshifted ASCII, data2: shifted ASCII, data3: modifiers
-	EV_GUI_KeyRepeat,		// same
-	EV_GUI_KeyUp,			// same
-	EV_GUI_Char,			// data1: translated character (for user text input), data2: alt down?
-	EV_GUI_FirstMouseEvent,
-		EV_GUI_MouseMove,
-		EV_GUI_LButtonDown,
-		EV_GUI_LButtonUp,
-		EV_GUI_LButtonDblClick,
-		EV_GUI_MButtonDown,
-		EV_GUI_MButtonUp,
-		EV_GUI_MButtonDblClick,
-		EV_GUI_RButtonDown,
-		EV_GUI_RButtonUp,
-		EV_GUI_RButtonDblClick,
-		EV_GUI_WheelUp,			// data3: shift/ctrl/alt
-		EV_GUI_WheelDown,		// "
-		EV_GUI_WheelRight,		// "
-		EV_GUI_WheelLeft,		// "
-		EV_GUI_BackButtonDown,
-		EV_GUI_BackButtonUp,
-		EV_GUI_FwdButtonDown,
-		EV_GUI_FwdButtonUp,
-	EV_GUI_LastMouseEvent,
-};
-
-enum GUIKeyModifiers
-{
-	GKM_SHIFT	= 1,
-	GKM_CTRL	= 2,
-	GKM_ALT		= 4,
-	GKM_META	= 8,
-	GKM_LBUTTON = 16
-};
-
-// Special codes for some GUI keys, including a few real ASCII codes.
-enum ESpecialGUIKeys
-{
-	GK_PGDN		= 1,
-	GK_PGUP		= 2,
-	GK_HOME		= 3,
-	GK_END		= 4,
-	GK_LEFT		= 5,
-	GK_RIGHT	= 6,
-	GK_ALERT	= 7,		// ASCII bell
-	GK_BACKSPACE= 8,		// ASCII
-	GK_TAB		= 9,		// ASCII
-	GK_LINEFEED	= 10,		// ASCII
-	GK_DOWN		= 10,
-	GK_VTAB		= 11,		// ASCII
-	GK_UP		= 11,
-	GK_FORMFEED	= 12,		// ASCII
-	GK_RETURN	= 13,		// ASCII
-	GK_F1		= 14,
-	GK_F2		= 15,
-	GK_F3		= 16,
-	GK_F4		= 17,
-	GK_F5		= 18,
-	GK_F6		= 19,
-	GK_F7		= 20,
-	GK_F8		= 21,
-	GK_F9		= 22,
-	GK_F10		= 23,
-	GK_F11		= 24,
-	GK_F12		= 25,
-	GK_DEL		= 26,
-	GK_ESCAPE	= 27,		// ASCII
-	GK_FREE1	= 28,
-	GK_FREE2	= 29,
-	GK_BACK		= 30,		// browser back key
-	GK_CESCAPE	= 31		// color escape
-};
-
-#endif //__D_GUI_H__
diff --git a/src/g_game.cpp b/src/g_game.cpp
index 7568ec7f8..41f1f5e8b 100644
--- a/src/g_game.cpp
+++ b/src/g_game.cpp
@@ -3086,7 +3086,6 @@ DEFINE_GLOBAL(playeringame)
 DEFINE_GLOBAL(PlayerClasses)
 DEFINE_GLOBAL_NAMED(Skins, PlayerSkins)
 DEFINE_GLOBAL(consoleplayer)
-DEFINE_GLOBAL_NAMED(PClass::AllClasses, AllClasses)
 DEFINE_GLOBAL_NAMED(PClassActor::AllActorClasses, AllActorClasses)
 DEFINE_GLOBAL_NAMED(primaryLevel, Level)
 DEFINE_GLOBAL(validcount)
diff --git a/src/gamedata/info.cpp b/src/gamedata/info.cpp
index 0530b7de3..364f34c07 100644
--- a/src/gamedata/info.cpp
+++ b/src/gamedata/info.cpp
@@ -510,31 +510,7 @@ void PClassActor::InitializeDefaults()
 			else memset(Meta, 0, MetaSize);
 		}
 	}
-
-	if (VMType != nullptr)	// purely internal classes have no symbol table
-	{
-		if (bRuntimeClass)
-		{
-			// Copy parent values from the parent defaults.
-			assert(ParentClass != nullptr);
-			if (Defaults != nullptr) ParentClass->InitializeSpecials(Defaults, ParentClass->Defaults, &PClass::SpecialInits);
-			for (const PField* field : Fields)
-			{
-				if (!(field->Flags & VARF_Native) && !(field->Flags & VARF_Meta))
-				{
-					field->Type->SetDefaultValue(Defaults, unsigned(field->Offset), &SpecialInits);
-				}
-			}
-		}
-		if (Meta != nullptr) ParentClass->InitializeSpecials(Meta, ParentClass->Meta, &PClass::MetaInits);
-		for (const PField* field : Fields)
-		{
-			if (!(field->Flags & VARF_Native) && (field->Flags & VARF_Meta))
-			{
-				field->Type->SetDefaultValue(Meta, unsigned(field->Offset), &MetaInits);
-			}
-		}
-	}
+	PClass::InitializeDefaults();
 }
 
 //==========================================================================
diff --git a/src/scripting/vmthunks.cpp b/src/scripting/vmthunks.cpp
index 6b8343f0a..782a7e24f 100644
--- a/src/scripting/vmthunks.cpp
+++ b/src/scripting/vmthunks.cpp
@@ -1607,22 +1607,6 @@ DEFINE_ACTION_FUNCTION_NATIVE(FLevelLocals, ReplaceTextures, ReplaceTextures)
 	return 0;
 }
 
-static int CheckForTexture(const FString& name, int type, int flags)
-{
-	return TexMan.CheckForTexture(name, static_cast<ETextureType>(type), flags).GetIndex();
-}
-
-DEFINE_ACTION_FUNCTION_NATIVE(_TexMan, CheckForTexture, CheckForTexture)
-{
-	PARAM_PROLOGUE;
-	PARAM_STRING(name);
-	PARAM_INT(type);
-	PARAM_INT(flags);
-	ACTION_RETURN_INT(CheckForTexture(name, type, flags));
-}
-
-
-
 //=====================================================================================
 //
 // secplane_t exports
@@ -2920,12 +2904,6 @@ DEFINE_FIELD(DHUDFont, mFont);
 
 DEFINE_GLOBAL(StatusBar);
 
-DEFINE_GLOBAL(Bindings)
 DEFINE_GLOBAL(AutomapBindings)
 
-DEFINE_GLOBAL_NAMED(mus_playing, musplaying);
-DEFINE_FIELD_X(MusPlayingInfo, MusPlayingInfo, name);
-DEFINE_FIELD_X(MusPlayingInfo, MusPlayingInfo, baseorder);
-DEFINE_FIELD_X(MusPlayingInfo, MusPlayingInfo, loop);
-
 DEFINE_GLOBAL(generic_ui)
diff --git a/src/scripting/zscript/zcc_compile_doom.cpp b/src/scripting/zscript/zcc_compile_doom.cpp
index 350253c04..8353d11f9 100644
--- a/src/scripting/zscript/zcc_compile_doom.cpp
+++ b/src/scripting/zscript/zcc_compile_doom.cpp
@@ -648,7 +648,7 @@ void ZCCDoomCompiler::InitDefaults()
 			if (c->Defaults.Size()) Error(c->cls, "%s: Non-actor classes may not have defaults", c->ClassType()->TypeName.GetChars());
 			if (c->ClassType()->ParentClass)
 			{
-				auto ti = static_cast<PClassActor *>(c->ClassType());
+				auto ti = c->ClassType();
 				ti->InitializeDefaults();
 			}
 		}
diff --git a/src/scripting/zscript/zcc_compile_doom.h b/src/scripting/zscript/zcc_compile_doom.h
index 24f1350c9..36d7a4680 100644
--- a/src/scripting/zscript/zcc_compile_doom.h
+++ b/src/scripting/zscript/zcc_compile_doom.h
@@ -24,7 +24,7 @@ private:
 	void DispatchScriptProperty(PProperty *prop, ZCC_PropertyStmt *property, AActor *defaults, Baggage &bag);
 	void ProcessDefaultProperty(PClassActor *cls, ZCC_PropertyStmt *prop, Baggage &bag);
 	void ProcessDefaultFlag(PClassActor *cls, ZCC_FlagStmt *flg);
-	void InitDefaults();
+	void InitDefaults() override final;
 	FxExpression *SetupActionFunction(PClass *cls, ZCC_TreeNode *af, int StateFlags);
 	void CompileStates();
 	int CheckActionKeyword(ZCC_FuncDeclarator *f, uint32_t &varflags, int useflags, ZCC_StructWork *c);