diff --git a/modules/juce_gui_extra/documents/juce_FileBasedDocument.cpp b/modules/juce_gui_extra/documents/juce_FileBasedDocument.cpp
index 2c966ee3a9..7be1056be2 100644
--- a/modules/juce_gui_extra/documents/juce_FileBasedDocument.cpp
+++ b/modules/juce_gui_extra/documents/juce_FileBasedDocument.cpp
@@ -72,7 +72,7 @@ public:
     }
 
     //==============================================================================
-    bool hasChangedSinceSaved()
+    bool hasChangedSinceSaved() const
     {
         return changedSinceSave;
     }