diff --git a/extras/Projucer/Source/Project/jucer_Project.cpp b/extras/Projucer/Source/Project/jucer_Project.cpp
index 988761f6c9..52c2b46f3b 100644
--- a/extras/Projucer/Source/Project/jucer_Project.cpp
+++ b/extras/Projucer/Source/Project/jucer_Project.cpp
@@ -456,12 +456,14 @@ Result Project::saveResourcesOnly (const File& file)
 //==============================================================================
 void Project::valueTreePropertyChanged (ValueTree& tree, const Identifier& property)
 {
-    if (tree.getParent() == tree)
+    if (tree.getRoot() == tree)
     {
         if (property == Ids::projectType)
             sendChangeMessage();
         else if (property == Ids::name)
             setTitle (projectRoot [Ids::name]);
+        else if (property == Ids::defines)
+            parsedPreprocessorDefs = parsePreprocessorDefs (preprocessorDefsValue.get());
 
         changed();
     }
@@ -853,11 +855,6 @@ String Project::getVersionAsHex() const
     return "0x" + String::toHexString (getVersionAsHexInteger());
 }
 
-StringPairArray Project::getPreprocessorDefs() const
-{
-    return parsePreprocessorDefs (projectRoot [Ids::defines]);
-}
-
 File Project::getBinaryDataCppFile (int index) const
 {
     const File cpp (getGeneratedCodeFolder().getChildFile ("BinaryData.cpp"));
diff --git a/extras/Projucer/Source/Project/jucer_Project.h b/extras/Projucer/Source/Project/jucer_Project.h
index 257b9d449e..80290e60f4 100644
--- a/extras/Projucer/Source/Project/jucer_Project.h
+++ b/extras/Projucer/Source/Project/jucer_Project.h
@@ -111,7 +111,7 @@ public:
 
     String getHeaderSearchPathsString() const            { return headerSearchPathsValue.get(); }
 
-    StringPairArray getPreprocessorDefs() const;
+    StringPairArray getPreprocessorDefs() const          { return parsedPreprocessorDefs; }
 
     int getMaxBinaryFileSize() const                     { return maxBinaryFileSizeValue.get(); }
     bool shouldIncludeBinaryInAppConfig() const          { return includeBinaryDataInAppConfigValue.get(); }
@@ -353,6 +353,7 @@ private:
     ScopedPointer<EnabledModuleList> enabledModulesList;
     bool isSaving;
     Time modificationTime;
+    StringPairArray parsedPreprocessorDefs;
 
     //==============================================================================
     void intialiseProjectValues();