https://github.com/synfig/synfig/issues/300
https://github.com/synfig/synfig/commit/4fcc3f490cc02498491b76e18e80d1be954d04be
--- src/gui/workarea.h.orig
+++ src/gui/workarea.h
@@ -130,7 +130,7 @@ class WorkAreaTile
 			  top + (surface ? cairo_image_surface_get_height(surface) : 0) ),
 		surface() { }
 
-	bool operator< (const WorkAreaTile &other) { return refresh_id < other.refresh_id; }
+	bool operator< (const WorkAreaTile &other) const { return refresh_id < other.refresh_id; }
 };
 
 class WorkAreaTileBook