diff --git a/modules/juce_browser_plugin_client/wrapper/juce_NPAPI_GlueCode.cpp b/modules/juce_browser_plugin_client/wrapper/juce_NPAPI_GlueCode.cpp
index e41feda6af..42748b9230 100644
--- a/modules/juce_browser_plugin_client/wrapper/juce_NPAPI_GlueCode.cpp
+++ b/modules/juce_browser_plugin_client/wrapper/juce_NPAPI_GlueCode.cpp
@@ -584,7 +584,7 @@ public:
 };
 
 //==============================================================================
-static NPIdentifier getIdentifierFromString (const var::identifier& s) noexcept
+static NPIdentifier getIdentifierFromString (const Identifier& s) noexcept
 {
     return browser.getstringidentifier (s.toString().toUTF8());
 }
@@ -601,6 +601,7 @@ class DynamicObjectWrappingNPObject   : public DynamicObject
 {
     NPP npp;
     NPObject* const source;
+    mutable var returnValue;
 
 public:
     DynamicObjectWrappingNPObject (NPP npp_, NPObject* const source_)
@@ -616,17 +617,20 @@ public:
         DBG ("num NP wrapper objs: " + String (--numDOWNP));
     }
 
-    var getProperty (const var::identifier& propertyName) const override
+    const var& getProperty (const Identifier& propertyName) const override
     {
         NPVariant result;
         VOID_TO_NPVARIANT (result);
         browser.getproperty (npp, source, getIdentifierFromString (propertyName), &result);
-        const var v (createValueFromNPVariant (npp, result));
+
+        // NB: this is just a workaorund for the return type being a reference - not too bothered
+        // about threading implications of this since this code will all soon be deprecated anyway.
+        returnValue = createValueFromNPVariant (npp, result);
         browser.releasevariantvalue (&result);
-        return v;
+        return returnValue;
     }
 
-    bool hasProperty (const var::identifier& propertyName) const override
+    bool hasProperty (const Identifier& propertyName) const override
     {
         NPVariant result;
         VOID_TO_NPVARIANT (result);
@@ -635,7 +639,7 @@ public:
         return hasProp;
     }
 
-    void setProperty (const var::identifier& propertyName, const var& newValue) override
+    void setProperty (const Identifier& propertyName, const var& newValue) override
     {
         NPVariant value;
         createNPVariantFromValue (npp, value, newValue);
@@ -644,12 +648,12 @@ public:
         browser.releasevariantvalue (&value);
     }
 
-    void removeProperty (const var::identifier& propertyName) override
+    void removeProperty (const Identifier& propertyName) override
     {
         browser.removeproperty (npp, source, getIdentifierFromString (propertyName));
     }
 
-    bool hasMethod (const var::identifier& methodName) const override
+    bool hasMethod (const Identifier& methodName) const override
     {
         return browser.hasmethod (npp, source, getIdentifierFromString (methodName));
     }
@@ -721,7 +725,7 @@ private:
     bool invoke (NPIdentifier name, const NPVariant* args, uint32_t argCount, NPVariant* out)
     {
         DynamicObject* const o = object.getDynamicObject();
-        const var::identifier methodName (identifierToString (name));
+        const Identifier methodName (identifierToString (name));
 
         if (o == nullptr || ! o->hasMethod (methodName))
             return false;
@@ -761,7 +765,7 @@ private:
     bool getProperty (NPIdentifier name, NPVariant* out)
     {
         DynamicObject* const o = object.getDynamicObject();
-        const var::identifier propName (identifierToString (name));
+        const Identifier propName (identifierToString (name));
 
         if (o == nullptr || ! o->hasProperty (propName))
             return false;
@@ -788,7 +792,7 @@ private:
     bool removeProperty (NPIdentifier name)
     {
         DynamicObject* const o = object.getDynamicObject();
-        const var::identifier propName (identifierToString (name));
+        const Identifier propName (identifierToString (name));
 
         if (o == nullptr || ! o->hasProperty (propName))
             return false;
@@ -806,10 +810,10 @@ private:
     NPP npp;
     var object;
 
-    static var::identifier identifierToString (NPIdentifier id)
+    static Identifier identifierToString (NPIdentifier id)
     {
         NPUTF8* const name = browser.utf8fromidentifier (id);
-        const var::identifier result ((const char*) name);
+        const Identifier result ((const char*) name);
         browser.memfree (name);
         return result;
     }
diff --git a/modules/juce_core/containers/juce_NamedValueSet.cpp b/modules/juce_core/containers/juce_NamedValueSet.cpp
index 504ab784f4..2c153e1f19 100644
--- a/modules/juce_core/containers/juce_NamedValueSet.cpp
+++ b/modules/juce_core/containers/juce_NamedValueSet.cpp
@@ -29,7 +29,7 @@
 struct NamedValueSet::NamedValue
 {
     NamedValue() noexcept {}
-    NamedValue (Identifier n, const var& v)  : name (n), value (v) {}
+    NamedValue (const Identifier& n, const var& v)  : name (n), value (v) {}
     NamedValue (const NamedValue& other) : name (other.name), value (other.value) {}
 
    #if JUCE_COMPILER_SUPPORTS_MOVE_SEMANTICS
@@ -39,7 +39,9 @@ struct NamedValueSet::NamedValue
     {
     }
 
-    NamedValue (Identifier n, var&& v)  : name (n), value (static_cast<var&&> (v))
+    NamedValue (Identifier&& n, var&& v)
+        : name (static_cast<Identifier&&> (n)),
+          value (static_cast<var&&> (v))
     {
     }
 
diff --git a/modules/juce_core/containers/juce_Variant.cpp b/modules/juce_core/containers/juce_Variant.cpp
index 833d7927a8..0cad685920 100644
--- a/modules/juce_core/containers/juce_Variant.cpp
+++ b/modules/juce_core/containers/juce_Variant.cpp
@@ -576,7 +576,7 @@ var var::clone() const noexcept
 }
 
 //==============================================================================
-const var& var::operator[] (Identifier propertyName) const
+const var& var::operator[] (const Identifier& propertyName) const
 {
     if (DynamicObject* const o = getDynamicObject())
         return o->getProperty (propertyName);
@@ -589,7 +589,7 @@ const var& var::operator[] (const char* const propertyName) const
     return operator[] (Identifier (propertyName));
 }
 
-var var::getProperty (const Identifier propertyName, const var& defaultReturnValue) const
+var var::getProperty (const Identifier& propertyName, const var& defaultReturnValue) const
 {
     if (DynamicObject* const o = getDynamicObject())
         return o->getProperties().getWithDefault (propertyName, defaultReturnValue);
@@ -602,7 +602,7 @@ var::NativeFunction var::getNativeFunction() const
     return isMethod() ? value.methodValue : nullptr;
 }
 
-var var::invoke (Identifier method, const var* arguments, int numArguments) const
+var var::invoke (const Identifier& method, const var* arguments, int numArguments) const
 {
     if (DynamicObject* const o = getDynamicObject())
         return o->invokeMethod (method, var::NativeFunctionArgs (*this, arguments, numArguments));
@@ -610,35 +610,35 @@ var var::invoke (Identifier method, const var* arguments, int numArguments) cons
     return var();
 }
 
-var var::call (const Identifier method) const
+var var::call (const Identifier& method) const
 {
     return invoke (method, nullptr, 0);
 }
 
-var var::call (const Identifier method, const var& arg1) const
+var var::call (const Identifier& method, const var& arg1) const
 {
     return invoke (method, &arg1, 1);
 }
 
-var var::call (const Identifier method, const var& arg1, const var& arg2) const
+var var::call (const Identifier& method, const var& arg1, const var& arg2) const
 {
     var args[] = { arg1, arg2 };
     return invoke (method, args, 2);
 }
 
-var var::call (const Identifier method, const var& arg1, const var& arg2, const var& arg3)
+var var::call (const Identifier& method, const var& arg1, const var& arg2, const var& arg3)
 {
     var args[] = { arg1, arg2, arg3 };
     return invoke (method, args, 3);
 }
 
-var var::call (const Identifier method, const var& arg1, const var& arg2, const var& arg3, const var& arg4) const
+var var::call (const Identifier& method, const var& arg1, const var& arg2, const var& arg3, const var& arg4) const
 {
     var args[] = { arg1, arg2, arg3, arg4 };
     return invoke (method, args, 4);
 }
 
-var var::call (const Identifier method, const var& arg1, const var& arg2, const var& arg3, const var& arg4, const var& arg5) const
+var var::call (const Identifier& method, const var& arg1, const var& arg2, const var& arg3, const var& arg4, const var& arg5) const
 {
     var args[] = { arg1, arg2, arg3, arg4, arg5 };
     return invoke (method, args, 5);
diff --git a/modules/juce_core/containers/juce_Variant.h b/modules/juce_core/containers/juce_Variant.h
index 1e0f03cf56..ed624f4d95 100644
--- a/modules/juce_core/containers/juce_Variant.h
+++ b/modules/juce_core/containers/juce_Variant.h
@@ -62,7 +62,6 @@ public:
     };
 
     typedef var (*NativeFunction) (const NativeFunctionArgs&);
-    typedef Identifier identifier;
 
     //==============================================================================
     /** Creates a void variant. */
@@ -242,27 +241,27 @@ public:
 
     //==============================================================================
     /** If this variant is an object, this returns one of its properties. */
-    const var& operator[] (Identifier propertyName) const;
+    const var& operator[] (const Identifier& propertyName) const;
     /** If this variant is an object, this returns one of its properties. */
     const var& operator[] (const char* propertyName) const;
     /** If this variant is an object, this returns one of its properties, or a default
         fallback value if the property is not set. */
-    var getProperty (Identifier propertyName, const var& defaultReturnValue) const;
+    var getProperty (const Identifier& propertyName, const var& defaultReturnValue) const;
 
     /** Invokes a named method call with no arguments. */
-    var call (Identifier method) const;
+    var call (const Identifier& method) const;
     /** Invokes a named method call with one argument. */
-    var call (Identifier method, const var& arg1) const;
+    var call (const Identifier& method, const var& arg1) const;
     /** Invokes a named method call with 2 arguments. */
-    var call (Identifier method, const var& arg1, const var& arg2) const;
+    var call (const Identifier& method, const var& arg1, const var& arg2) const;
     /** Invokes a named method call with 3 arguments. */
-    var call (Identifier method, const var& arg1, const var& arg2, const var& arg3);
+    var call (const Identifier& method, const var& arg1, const var& arg2, const var& arg3);
     /** Invokes a named method call with 4 arguments. */
-    var call (Identifier method, const var& arg1, const var& arg2, const var& arg3, const var& arg4) const;
+    var call (const Identifier& method, const var& arg1, const var& arg2, const var& arg3, const var& arg4) const;
     /** Invokes a named method call with 5 arguments. */
-    var call (Identifier method, const var& arg1, const var& arg2, const var& arg3, const var& arg4, const var& arg5) const;
+    var call (const Identifier& method, const var& arg1, const var& arg2, const var& arg3, const var& arg4, const var& arg5) const;
     /** Invokes a named method call with a list of arguments. */
-    var invoke (Identifier method, const var* arguments, int numArguments) const;
+    var invoke (const Identifier& method, const var* arguments, int numArguments) const;
     /** If this object is a method, this returns the function pointer. */
     NativeFunction getNativeFunction() const;
 
diff --git a/modules/juce_core/text/juce_Identifier.cpp b/modules/juce_core/text/juce_Identifier.cpp
index 4d9d3ea55f..04cfd13d1c 100644
--- a/modules/juce_core/text/juce_Identifier.cpp
+++ b/modules/juce_core/text/juce_Identifier.cpp
@@ -31,7 +31,17 @@ Identifier::~Identifier() noexcept {}
 
 Identifier::Identifier (const Identifier& other) noexcept  : name (other.name) {}
 
-Identifier& Identifier::operator= (const Identifier other) noexcept
+#if JUCE_COMPILER_SUPPORTS_MOVE_SEMANTICS
+Identifier::Identifier (Identifier&& other) noexcept : name (static_cast<String&&> (other.name)) {}
+
+Identifier& Identifier::operator= (Identifier&& other) noexcept
+{
+    name = static_cast<String&&> (other.name);
+    return *this;
+}
+#endif
+
+Identifier& Identifier::operator= (const Identifier& other) noexcept
 {
     name = other.name;
     return *this;
diff --git a/modules/juce_core/text/juce_Identifier.h b/modules/juce_core/text/juce_Identifier.h
index f60eec8d45..0abc1ae4ac 100644
--- a/modules/juce_core/text/juce_Identifier.h
+++ b/modules/juce_core/text/juce_Identifier.h
@@ -68,16 +68,24 @@ public:
     Identifier (const Identifier& other) noexcept;
 
     /** Creates a copy of another identifier. */
-    Identifier& operator= (const Identifier other) noexcept;
+    Identifier& operator= (const Identifier& other) noexcept;
+
+   #if JUCE_COMPILER_SUPPORTS_MOVE_SEMANTICS
+    /** Creates a copy of another identifier. */
+    Identifier (Identifier&& other) noexcept;
+
+    /** Creates a copy of another identifier. */
+    Identifier& operator= (Identifier&& other) noexcept;
+   #endif
 
     /** Destructor */
     ~Identifier() noexcept;
 
     /** Compares two identifiers. This is a very fast operation. */
-    inline bool operator== (Identifier other) const noexcept            { return name.getCharPointer() == other.name.getCharPointer(); }
+    inline bool operator== (const Identifier& other) const noexcept     { return name.getCharPointer() == other.name.getCharPointer(); }
 
     /** Compares two identifiers. This is a very fast operation. */
-    inline bool operator!= (Identifier other) const noexcept            { return name.getCharPointer() != other.name.getCharPointer(); }
+    inline bool operator!= (const Identifier& other) const noexcept     { return name.getCharPointer() != other.name.getCharPointer(); }
 
     /** Compares the identifier with a string. */
     inline bool operator== (StringRef other) const noexcept             { return name == other; }
diff --git a/modules/juce_data_structures/values/juce_ValueTree.cpp b/modules/juce_data_structures/values/juce_ValueTree.cpp
index 43cfc564c7..1efcb0b099 100644
--- a/modules/juce_data_structures/values/juce_ValueTree.cpp
+++ b/modules/juce_data_structures/values/juce_ValueTree.cpp
@@ -27,7 +27,7 @@ class ValueTree::SharedObject  : public ReferenceCountedObject
 public:
     typedef ReferenceCountedObjectPtr<SharedObject> Ptr;
 
-    explicit SharedObject (Identifier t) noexcept
+    explicit SharedObject (const Identifier& t) noexcept
         : type (t), parent (nullptr)
     {
     }
@@ -126,7 +126,7 @@ public:
         }
     }
 
-    void sendPropertyChangeMessage (const Identifier property)
+    void sendPropertyChangeMessage (const Identifier& property)
     {
         ValueTree tree (this);
 
@@ -169,7 +169,7 @@ public:
         callListeners (&ValueTree::Listener::valueTreeParentChanged, tree);
     }
 
-    void setProperty (const Identifier name, const var& newValue, UndoManager* const undoManager)
+    void setProperty (const Identifier& name, const var& newValue, UndoManager* const undoManager)
     {
         if (undoManager == nullptr)
         {
@@ -190,12 +190,12 @@ public:
         }
     }
 
-    bool hasProperty (const Identifier name) const noexcept
+    bool hasProperty (const Identifier& name) const noexcept
     {
         return properties.contains (name);
     }
 
-    void removeProperty (const Identifier name, UndoManager* const undoManager)
+    void removeProperty (const Identifier& name, UndoManager* const undoManager)
     {
         if (undoManager == nullptr)
         {
@@ -238,7 +238,7 @@ public:
             setProperty (source.properties.getName(i), source.properties.getValueAt(i), undoManager);
     }
 
-    ValueTree getChildWithName (const Identifier typeToMatch) const
+    ValueTree getChildWithName (const Identifier& typeToMatch) const
     {
         for (int i = 0; i < children.size(); ++i)
         {
@@ -250,7 +250,7 @@ public:
         return ValueTree();
     }
 
-    ValueTree getOrCreateChildWithName (const Identifier typeToMatch, UndoManager* undoManager)
+    ValueTree getOrCreateChildWithName (const Identifier& typeToMatch, UndoManager* undoManager)
     {
         for (int i = 0; i < children.size(); ++i)
         {
@@ -265,7 +265,7 @@ public:
 
     }
 
-    ValueTree getChildWithProperty (const Identifier propertyName, const var& propertyValue) const
+    ValueTree getChildWithProperty (const Identifier& propertyName, const var& propertyValue) const
     {
         for (int i = 0; i < children.size(); ++i)
         {
@@ -458,7 +458,7 @@ public:
     class SetPropertyAction  : public UndoableAction
     {
     public:
-        SetPropertyAction (SharedObject* const so, const Identifier propertyName,
+        SetPropertyAction (SharedObject* const so, const Identifier& propertyName,
                            const var& newVal, const var& oldVal, bool isAdding, bool isDeleting)
             : target (so), name (propertyName), newValue (newVal), oldValue (oldVal),
               isAddingNewProperty (isAdding), isDeletingProperty (isDeleting)
@@ -629,7 +629,7 @@ ValueTree::ValueTree() noexcept
 
 const ValueTree ValueTree::invalid;
 
-ValueTree::ValueTree (Identifier type)  : object (new ValueTree::SharedObject (type))
+ValueTree::ValueTree (const Identifier& type)  : object (new ValueTree::SharedObject (type))
 {
     jassert (type.toString().isNotEmpty()); // All objects must be given a sensible type name!
 }
@@ -702,7 +702,7 @@ ValueTree ValueTree::createCopy() const
     return ValueTree (createCopyIfNotNull (object.get()));
 }
 
-bool ValueTree::hasType (const Identifier typeName) const
+bool ValueTree::hasType (const Identifier& typeName) const
 {
     return object != nullptr && object->type == typeName;
 }
@@ -727,24 +727,23 @@ ValueTree ValueTree::getSibling (const int delta) const
     return ValueTree (object->parent->children.getObjectPointer (index));
 }
 
-const var& ValueTree::operator[] (const Identifier name) const
+const var& ValueTree::operator[] (const Identifier& name) const
 {
     return object == nullptr ? var::null : object->properties[name];
 }
 
-const var& ValueTree::getProperty (const Identifier name) const
+const var& ValueTree::getProperty (const Identifier& name) const
 {
     return object == nullptr ? var::null : object->properties[name];
 }
 
-var ValueTree::getProperty (const Identifier name, const var& defaultReturnValue) const
+var ValueTree::getProperty (const Identifier& name, const var& defaultReturnValue) const
 {
     return object == nullptr ? defaultReturnValue
                              : object->properties.getWithDefault (name, defaultReturnValue);
 }
 
-ValueTree& ValueTree::setProperty (const Identifier name, const var& newValue,
-                                   UndoManager* const undoManager)
+ValueTree& ValueTree::setProperty (const Identifier& name, const var& newValue, UndoManager* undoManager)
 {
     jassert (name.toString().isNotEmpty()); // Must have a valid property name!
     jassert (object != nullptr); // Trying to add a property to a null ValueTree will fail!
@@ -755,12 +754,12 @@ ValueTree& ValueTree::setProperty (const Identifier name, const var& newValue,
     return *this;
 }
 
-bool ValueTree::hasProperty (const Identifier name) const
+bool ValueTree::hasProperty (const Identifier& name) const
 {
     return object != nullptr && object->hasProperty (name);
 }
 
-void ValueTree::removeProperty (const Identifier name, UndoManager* const undoManager)
+void ValueTree::removeProperty (const Identifier& name, UndoManager* const undoManager)
 {
     if (object != nullptr)
         object->removeProperty (name, undoManager);
@@ -803,7 +802,7 @@ class ValueTreePropertyValueSource  : public Value::ValueSource,
                                       private ValueTree::Listener
 {
 public:
-    ValueTreePropertyValueSource (const ValueTree& vt, const Identifier prop, UndoManager* um)
+    ValueTreePropertyValueSource (const ValueTree& vt, const Identifier& prop, UndoManager* um)
         : tree (vt), property (prop), undoManager (um)
     {
         tree.addListener (this);
@@ -836,7 +835,7 @@ private:
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ValueTreePropertyValueSource)
 };
 
-Value ValueTree::getPropertyAsValue (const Identifier name, UndoManager* const undoManager)
+Value ValueTree::getPropertyAsValue (const Identifier& name, UndoManager* const undoManager)
 {
     return Value (new ValueTreePropertyValueSource (*this, name, undoManager));
 }
@@ -853,17 +852,17 @@ ValueTree ValueTree::getChild (int index) const
                                         : static_cast<SharedObject*> (nullptr));
 }
 
-ValueTree ValueTree::getChildWithName (const Identifier type) const
+ValueTree ValueTree::getChildWithName (const Identifier& type) const
 {
     return object != nullptr ? object->getChildWithName (type) : ValueTree();
 }
 
-ValueTree ValueTree::getOrCreateChildWithName (const Identifier type, UndoManager* undoManager)
+ValueTree ValueTree::getOrCreateChildWithName (const Identifier& type, UndoManager* undoManager)
 {
     return object != nullptr ? object->getOrCreateChildWithName (type, undoManager) : ValueTree();
 }
 
-ValueTree ValueTree::getChildWithProperty (const Identifier propertyName, const var& propertyValue) const
+ValueTree ValueTree::getChildWithProperty (const Identifier& propertyName, const var& propertyValue) const
 {
     return object != nullptr ? object->getChildWithProperty (propertyName, propertyValue) : ValueTree();
 }
@@ -945,7 +944,7 @@ void ValueTree::removeListener (Listener* listener)
         object->valueTreesWithListeners.removeValue (this);
 }
 
-void ValueTree::sendPropertyChangeMessage (const Identifier property)
+void ValueTree::sendPropertyChangeMessage (const Identifier& property)
 {
     if (object != nullptr)
         object->sendPropertyChangeMessage (property);
diff --git a/modules/juce_data_structures/values/juce_ValueTree.h b/modules/juce_data_structures/values/juce_ValueTree.h
index 9a9ccd16d7..78d870f8ce 100644
--- a/modules/juce_data_structures/values/juce_ValueTree.h
+++ b/modules/juce_data_structures/values/juce_ValueTree.h
@@ -79,7 +79,7 @@ public:
         Like an XmlElement, each ValueTree node has a type, which you can access with
         getType() and hasType().
     */
-    explicit ValueTree (Identifier type);
+    explicit ValueTree (const Identifier& type);
 
     /** Creates a reference to another ValueTree. */
     ValueTree (const ValueTree&);
@@ -134,7 +134,7 @@ public:
     /** Returns true if the node has this type.
         The comparison is case-sensitive.
     */
-    bool hasType (const Identifier typeName) const;
+    bool hasType (const Identifier& typeName) const;
 
     //==============================================================================
     /** Returns the value of a named property.
@@ -142,21 +142,21 @@ public:
         You can also use operator[] to get a property.
         @see var, setProperty, hasProperty
     */
-    const var& getProperty (const Identifier name) const;
+    const var& getProperty (const Identifier& name) const;
 
     /** Returns the value of a named property, or a user-specified default if the property doesn't exist.
         If no such property has been set, this will return the value of defaultReturnValue.
         You can also use operator[] and getProperty to get a property.
         @see var, getProperty, setProperty, hasProperty
     */
-    var getProperty (const Identifier name, const var& defaultReturnValue) const;
+    var getProperty (const Identifier& name, const var& defaultReturnValue) const;
 
     /** Returns the value of a named property.
         If no such property has been set, this will return a void variant. This is the same as
         calling getProperty().
         @see getProperty
     */
-    const var& operator[] (const Identifier name) const;
+    const var& operator[] (const Identifier& name) const;
 
     /** Changes a named property of the node.
         The name identifier must not be an empty string.
@@ -165,16 +165,16 @@ public:
         @see var, getProperty, removeProperty
         @returns a reference to the value tree, so that you can daisy-chain calls to this method.
     */
-    ValueTree& setProperty (const Identifier name, const var& newValue, UndoManager* undoManager);
+    ValueTree& setProperty (const Identifier& name, const var& newValue, UndoManager* undoManager);
 
     /** Returns true if the node contains a named property. */
-    bool hasProperty (const Identifier name) const;
+    bool hasProperty (const Identifier& name) const;
 
     /** Removes a property from the node.
         If the undoManager parameter is non-null, its UndoManager::perform() method will be used,
         so that this change can be undone.
     */
-    void removeProperty (const Identifier name, UndoManager* undoManager);
+    void removeProperty (const Identifier& name, UndoManager* undoManager);
 
     /** Removes all properties from the node.
         If the undoManager parameter is non-null, its UndoManager::perform() method will be used,
@@ -198,7 +198,7 @@ public:
         it needs to change the value. Attaching a Value::Listener to the value object will provide
         callbacks whenever the property changes.
     */
-    Value getPropertyAsValue (const Identifier name, UndoManager* undoManager);
+    Value getPropertyAsValue (const Identifier& name, UndoManager* undoManager);
 
     /** Overwrites all the properties in this tree with the properties of the source tree.
         Any properties that already exist will be updated; and new ones will be added, and
@@ -223,7 +223,7 @@ public:
         whether a node is valid).
         @see getOrCreateChildWithName
     */
-    ValueTree getChildWithName (const Identifier type) const;
+    ValueTree getChildWithName (const Identifier& type) const;
 
     /** Returns the first child node with the speficied type name, creating and adding
         a child with this name if there wasn't already one there.
@@ -232,7 +232,7 @@ public:
         the method on is itself invalid.
         @see getChildWithName
     */
-    ValueTree getOrCreateChildWithName (const Identifier type, UndoManager* undoManager);
+    ValueTree getOrCreateChildWithName (const Identifier& type, UndoManager* undoManager);
 
     /** Looks for the first child node that has the speficied property value.
 
@@ -242,7 +242,7 @@ public:
         If no such node is found, it'll return an invalid node. (See isValid() to find out
         whether a node is valid).
     */
-    ValueTree getChildWithProperty (const Identifier propertyName, const var& propertyValue) const;
+    ValueTree getChildWithProperty (const Identifier& propertyName, const var& propertyValue) const;
 
     /** Adds a child to this node.
 
@@ -453,7 +453,7 @@ public:
     /** Causes a property-change callback to be triggered for the specified property,
         calling any listeners that are registered.
     */
-    void sendPropertyChangeMessage (const Identifier property);
+    void sendPropertyChangeMessage (const Identifier& property);
 
     //==============================================================================
     /** This method uses a comparator object to sort the tree's children into order.