diff --git a/build/org.eclipse.cdt.make.ui/src/org/eclipse/cdt/make/internal/ui/editor/MakefileSourceConfiguration.java b/build/org.eclipse.cdt.make.ui/src/org/eclipse/cdt/make/internal/ui/editor/MakefileSourceConfiguration.java
index 1438b300e6d..df9046630b4 100644
--- a/build/org.eclipse.cdt.make.ui/src/org/eclipse/cdt/make/internal/ui/editor/MakefileSourceConfiguration.java
+++ b/build/org.eclipse.cdt.make.ui/src/org/eclipse/cdt/make/internal/ui/editor/MakefileSourceConfiguration.java
@@ -138,4 +138,11 @@ public class MakefileSourceConfiguration extends SourceViewerConfiguration {
 		return reconciler;
 	}
 
+	/* (non-Javadoc)
+	 * @see org.eclipse.jface.text.source.SourceViewerConfiguration#getDefaultPrefixes(org.eclipse.jface.text.source.ISourceViewer, java.lang.String)
+	 */
+	public String[] getDefaultPrefixes(ISourceViewer sourceViewer, String contentType) {
+		return new String[]{"#"};
+	}
+
 }