diff --git a/src/Shuttle.cpp b/src/Shuttle.cpp
index 4a3cccff4..a17891b56 100644
--- a/src/Shuttle.cpp
+++ b/src/Shuttle.cpp
@@ -523,129 +523,6 @@ void ShuttleSetAutomation::DefineEnum( int &var, const wxChar * key, const int v
       var = temp;
 }
 
-bool ShuttleGetDefinition::IsOptional(){
-   bool result = pOptionalFlag !=NULL;
-   pOptionalFlag = NULL;
-   return result;
-}
-
-// Definition distinguishes optional from not.
-ShuttleParams & ShuttleGetDefinition::Optional( bool & var ){ 
-   pOptionalFlag = &var;
-   return *this;
-};
-
-ShuttleGetDefinition::ShuttleGetDefinition( CommandMessageTarget & target ) : CommandMessageTargetDecorator( target )
-{
-}
-
-// JSON definitions.
-void ShuttleGetDefinition::Define( bool & var,     const wxChar * key, const bool vdefault, const bool vmin, const bool vmax, const bool vscl )
-{
-   StartStruct();
-   AddItem( wxString(key), "key" );
-   AddItem( "bool", "type" );
-   if( IsOptional() )
-      AddItem( "unchanged", "default" );
-   else
-      AddItem( vdefault ? "True" : "False", "default" );
-   EndStruct();
-}
-
-void ShuttleGetDefinition::Define( int & var,      const wxChar * key, const int vdefault, const int vmin, const int vmax, const int vscl )
-{
-   StartStruct();
-   AddItem( wxString(key), "key" );
-   AddItem( "int", "type" );
-   if( IsOptional() )
-      AddItem( "unchanged", "default" );
-   else
-      AddItem( (double)vdefault, "default"  );
-   EndStruct();
-}
-
-void ShuttleGetDefinition::Define( size_t & var,      const wxChar * key, const int vdefault, const int vmin, const int vmax, const int vscl )
-{
-   StartStruct();
-   AddItem( wxString(key), "key" );
-   AddItem( "size_t", "type" );
-   if( IsOptional() )
-      AddItem( "unchanged", "default" );
-   else
-      AddItem( (double)vdefault, "default"  );
-   EndStruct();
-
-}
-
-void ShuttleGetDefinition::Define( float & var,   const wxChar * key, const float vdefault, const float vmin, const float vmax, const float vscl )
-{
-   StartStruct();
-   AddItem( wxString(key), "key" );
-   AddItem( "float", "type" );
-   if( IsOptional() )
-      AddItem( "unchanged", "default" );
-   else
-      AddItem( (double)vdefault, "default"  );
-   EndStruct();
-}
-
-void ShuttleGetDefinition::Define( double & var,   const wxChar * key, const float vdefault, const float vmin, const float vmax, const float vscl )
-{
-   StartStruct();
-   AddItem( wxString(key), "key" );
-   AddItem( "float", "type" );
-   if( IsOptional() )
-      AddItem( "unchanged", "default" );
-   else
-      AddItem( (double)vdefault, "default"  );
-   EndStruct();
-}
-
-void ShuttleGetDefinition::Define( double & var,   const wxChar * key, const double vdefault, const double vmin, const double vmax, const double vscl )
-{
-   StartStruct();
-   AddItem( wxString(key), "key" );
-   AddItem( "double", "type" );
-   if( IsOptional() )
-      AddItem( "unchanged", "default" );
-   else
-      AddItem( (double)vdefault, "default"  );
-   EndStruct();
-}
-
-
-void ShuttleGetDefinition::Define( wxString &var, const wxChar * key, const wxString vdefault, const wxString vmin, const wxString vmax, const wxString vscl )
-{
-   StartStruct();
-   AddItem( wxString(key), "key" );
-   AddItem( "string", "type" );
-   if( IsOptional() )
-      AddItem( "unchanged", "default" );
-   else
-      AddItem( vdefault, "default"  );
-   EndStruct();
-}
-
-
-void ShuttleGetDefinition::DefineEnum( int &var,
-   const wxChar * key, const int vdefault,
-   const EnumValueSymbol strings[], size_t nStrings )
-{
-   StartStruct();
-   AddItem( wxString(key), "key" );
-   AddItem( "enum", "type" );
-   if( IsOptional() )
-      AddItem( "unchanged", "default" );
-   else
-      AddItem( strings[vdefault].Internal(), "default"  );
-   StartField( "enum" );
-   StartArray();
-   for( size_t i = 0; i < nStrings; i++ )
-      AddItem( strings[i].Internal() );
-   EndArray();
-   EndField();
-   EndStruct();
-}
 
 #ifdef _MSC_VER
 // If this is compiled with MSVC (Visual Studio)
diff --git a/src/Shuttle.h b/src/Shuttle.h
index ad9ad0971..36a20fb62 100644
--- a/src/Shuttle.h
+++ b/src/Shuttle.h
@@ -11,7 +11,6 @@
 #ifndef __AUDACITY_SHUTTLE__
 #define __AUDACITY_SHUTTLE__
 
-#include "commands/CommandTargets.h"
 #include "../include/audacity/ComponentInterface.h"
 
 class ComponentInterfaceSymbol;
@@ -123,27 +122,6 @@ public:
       const EnumValueSymbol strings[], size_t nStrings ) override;
 };
 
-/**************************************************************************//**
-\brief Shuttle that retrieves a JSON format definition of a command's parameters.
-********************************************************************************/
-class ShuttleGetDefinition : public ShuttleParams, public CommandMessageTargetDecorator
-{
-public:
-   ShuttleGetDefinition( CommandMessageTarget & target );
-   wxString Result;
-   bool IsOptional();
-   ShuttleParams & Optional( bool & var ) override;
-   void Define( bool & var,     const wxChar * key, const bool vdefault, const bool vmin, const bool vmax, const bool vscl ) override;
-   void Define( int & var,      const wxChar * key, const int vdefault, const int vmin, const int vmax, const int vscl ) override;
-   void Define( size_t & var,   const wxChar * key, const int vdefault, const int vmin, const int vmax, const int vscl ) override;
-   void Define( float & var,    const wxChar * key, const float vdefault, const float vmin, const float vmax, const float vscl ) override;
-   void Define( double & var,   const wxChar * key, const float vdefault, const float vmin, const float vmax, const float vscl ) override;
-   void Define( double & var,   const wxChar * key, const double vdefault, const double vmin, const double vmax, const double vscl ) override;
-   void Define( wxString &var,  const wxChar * key, const wxString vdefault, const wxString vmin, const wxString vmax, const wxString vscl ) override;
-   void DefineEnum( int &var, const wxChar * key, const int vdefault,
-      const EnumValueSymbol strings[], size_t nStrings ) override;
-};
-
 
 /**************************************************************************//**
 \brief Shuttle that sets parameters to their default values.
diff --git a/src/ShuttleGetDefinition.cpp b/src/ShuttleGetDefinition.cpp
index e69de29bb..1655875ca 100644
--- a/src/ShuttleGetDefinition.cpp
+++ b/src/ShuttleGetDefinition.cpp
@@ -0,0 +1,135 @@
+/**********************************************************************
+
+  Audacity: A Digital Audio Editor
+
+  ShuttleGetDefinition.cpp
+
+  Paul Licameli split this out of Shuttle.cpp
+
+**********************************************************************/
+
+#include "ShuttleGetDefinition.h"
+
+bool ShuttleGetDefinition::IsOptional(){
+   bool result = pOptionalFlag !=NULL;
+   pOptionalFlag = NULL;
+   return result;
+}
+
+// Definition distinguishes optional from not.
+ShuttleParams & ShuttleGetDefinition::Optional( bool & var ){
+   pOptionalFlag = &var;
+   return *this;
+};
+
+ShuttleGetDefinition::ShuttleGetDefinition( CommandMessageTarget & target ) : CommandMessageTargetDecorator( target )
+{
+}
+
+// JSON definitions.
+void ShuttleGetDefinition::Define( bool & var,     const wxChar * key, const bool vdefault, const bool vmin, const bool vmax, const bool vscl )
+{
+   StartStruct();
+   AddItem( wxString(key), "key" );
+   AddItem( "bool", "type" );
+   if( IsOptional() )
+      AddItem( "unchanged", "default" );
+   else
+      AddItem( vdefault ? "True" : "False", "default" );
+   EndStruct();
+}
+
+void ShuttleGetDefinition::Define( int & var,      const wxChar * key, const int vdefault, const int vmin, const int vmax, const int vscl )
+{
+   StartStruct();
+   AddItem( wxString(key), "key" );
+   AddItem( "int", "type" );
+   if( IsOptional() )
+      AddItem( "unchanged", "default" );
+   else
+      AddItem( (double)vdefault, "default"  );
+   EndStruct();
+}
+
+void ShuttleGetDefinition::Define( size_t & var,      const wxChar * key, const int vdefault, const int vmin, const int vmax, const int vscl )
+{
+   StartStruct();
+   AddItem( wxString(key), "key" );
+   AddItem( "size_t", "type" );
+   if( IsOptional() )
+      AddItem( "unchanged", "default" );
+   else
+      AddItem( (double)vdefault, "default"  );
+   EndStruct();
+   
+}
+
+void ShuttleGetDefinition::Define( float & var,   const wxChar * key, const float vdefault, const float vmin, const float vmax, const float vscl )
+{
+   StartStruct();
+   AddItem( wxString(key), "key" );
+   AddItem( "float", "type" );
+   if( IsOptional() )
+      AddItem( "unchanged", "default" );
+   else
+      AddItem( (double)vdefault, "default"  );
+   EndStruct();
+}
+
+void ShuttleGetDefinition::Define( double & var,   const wxChar * key, const float vdefault, const float vmin, const float vmax, const float vscl )
+{
+   StartStruct();
+   AddItem( wxString(key), "key" );
+   AddItem( "float", "type" );
+   if( IsOptional() )
+      AddItem( "unchanged", "default" );
+   else
+      AddItem( (double)vdefault, "default"  );
+   EndStruct();
+}
+
+void ShuttleGetDefinition::Define( double & var,   const wxChar * key, const double vdefault, const double vmin, const double vmax, const double vscl )
+{
+   StartStruct();
+   AddItem( wxString(key), "key" );
+   AddItem( "double", "type" );
+   if( IsOptional() )
+      AddItem( "unchanged", "default" );
+   else
+      AddItem( (double)vdefault, "default"  );
+   EndStruct();
+}
+
+
+void ShuttleGetDefinition::Define( wxString &var, const wxChar * key, const wxString vdefault, const wxString vmin, const wxString vmax, const wxString vscl )
+{
+   StartStruct();
+   AddItem( wxString(key), "key" );
+   AddItem( "string", "type" );
+   if( IsOptional() )
+      AddItem( "unchanged", "default" );
+   else
+      AddItem( vdefault, "default"  );
+   EndStruct();
+}
+
+
+void ShuttleGetDefinition::DefineEnum( int &var,
+                                      const wxChar * key, const int vdefault,
+                                      const EnumValueSymbol strings[], size_t nStrings )
+{
+   StartStruct();
+   AddItem( wxString(key), "key" );
+   AddItem( "enum", "type" );
+   if( IsOptional() )
+      AddItem( "unchanged", "default" );
+   else
+      AddItem( strings[vdefault].Internal(), "default"  );
+   StartField( "enum" );
+   StartArray();
+   for( size_t i = 0; i < nStrings; i++ )
+      AddItem( strings[i].Internal() );
+   EndArray();
+   EndField();
+   EndStruct();
+}
diff --git a/src/ShuttleGetDefinition.h b/src/ShuttleGetDefinition.h
index e69de29bb..558352f72 100644
--- a/src/ShuttleGetDefinition.h
+++ b/src/ShuttleGetDefinition.h
@@ -0,0 +1,38 @@
+/**********************************************************************
+
+  Audacity: A Digital Audio Editor
+
+  ShuttleGetDefinition.h
+
+  Paul Licameli split this out of Shuttle.h
+
+**********************************************************************/
+
+#ifndef __AUDACITY_SHUTTLE_GET_DEFINITION__
+#define __AUDACITY_SHUTTLE_GET_DEFINITION__
+
+#include "Shuttle.h" // to inherit
+#include "commands/CommandTargets.h" // to inherit
+
+/**************************************************************************//**
+\brief Shuttle that retrieves a JSON format definition of a command's parameters.
+********************************************************************************/
+class ShuttleGetDefinition : public ShuttleParams, public CommandMessageTargetDecorator
+{
+public:
+   ShuttleGetDefinition( CommandMessageTarget & target );
+   wxString Result;
+   bool IsOptional();
+   ShuttleParams & Optional( bool & var ) override;
+   void Define( bool & var,     const wxChar * key, const bool vdefault, const bool vmin, const bool vmax, const bool vscl ) override;
+   void Define( int & var,      const wxChar * key, const int vdefault, const int vmin, const int vmax, const int vscl ) override;
+   void Define( size_t & var,   const wxChar * key, const int vdefault, const int vmin, const int vmax, const int vscl ) override;
+   void Define( float & var,    const wxChar * key, const float vdefault, const float vmin, const float vmax, const float vscl ) override;
+   void Define( double & var,   const wxChar * key, const float vdefault, const float vmin, const float vmax, const float vscl ) override;
+   void Define( double & var,   const wxChar * key, const double vdefault, const double vmin, const double vmax, const double vscl ) override;
+   void Define( wxString &var,  const wxChar * key, const wxString vdefault, const wxString vmin, const wxString vmax, const wxString vscl ) override;
+   void DefineEnum( int &var, const wxChar * key, const int vdefault,
+      const EnumValueSymbol strings[], size_t nStrings ) override;
+};
+
+#endif
diff --git a/src/commands/CommandBuilder.cpp b/src/commands/CommandBuilder.cpp
index a815fff1e..5b2da4cb1 100644
--- a/src/commands/CommandBuilder.cpp
+++ b/src/commands/CommandBuilder.cpp
@@ -25,10 +25,11 @@ system by constructing BatchCommandEval objects.
 #include "CommandBuilder.h"
 
 #include "CommandDirectory.h"
-#include "../Shuttle.h"
 #include "BatchEvalCommand.h"
 #include "ScriptCommandRelay.h"
 #include "CommandContext.h"
+#include "CommandTargets.h"
+#include "Shuttle.h"
 
 CommandBuilder::CommandBuilder(const wxString &cmdString)
    : mValid(false)
diff --git a/src/commands/GetInfoCommand.cpp b/src/commands/GetInfoCommand.cpp
index 1654cf92a..b90b65582 100644
--- a/src/commands/GetInfoCommand.cpp
+++ b/src/commands/GetInfoCommand.cpp
@@ -25,6 +25,7 @@ This class now lists
 
 #include "../Project.h"
 #include "CommandManager.h"
+#include "CommandTargets.h"
 #include "../effects/EffectManager.h"
 #include "../widgets/Overlay.h"
 #include "../TrackPanel.h"
diff --git a/src/effects/EffectManager.cpp b/src/effects/EffectManager.cpp
index 94039c6f8..dd9220767 100644
--- a/src/effects/EffectManager.cpp
+++ b/src/effects/EffectManager.cpp
@@ -33,7 +33,7 @@ effects.
 #include "EffectRack.h"
 #endif
 
-#include "../Shuttle.h"
+#include "../ShuttleGetDefinition.h"
 #include "../commands/CommandContext.h"
 #include "../PluginManager.h"
 
diff --git a/src/effects/nyquist/Nyquist.cpp b/src/effects/nyquist/Nyquist.cpp
index a22b74a0f..ca1c86116 100644
--- a/src/effects/nyquist/Nyquist.cpp
+++ b/src/effects/nyquist/Nyquist.cpp
@@ -61,7 +61,7 @@ effects from this one class.
 #include "../../TimeTrack.h"
 #include "../../prefs/SpectrogramSettings.h"
 #include "../../Project.h"
-#include "../../Shuttle.h"
+#include "../../ShuttleGetDefinition.h"
 #include "../../ShuttleGui.h"
 #include "../../WaveClip.h"
 #include "../../WaveTrack.h"