diff --git a/src/Experimental.h b/src/Experimental.h
index 46b90561c..b310e215f 100644
--- a/src/Experimental.h
+++ b/src/Experimental.h
@@ -208,4 +208,10 @@
 // interpolating in frequency domain.
 #define EXPERIMENTAL_ZERO_PADDED_SPECTROGRAMS
 
+// PRL 11 Jul 2017
+// Highlight more things in TrackPanel when the mouse moves over them,
+// using delibrately ugly pens and brushes until there is better cooperation
+// with themes
+//#define EXPERIMENTAL_TRACK_PANEL_HIGHLIGHTING
+
 #endif