Derive Slice from sigc::trackable as it connects to external signals

diff --git a/source/io/slice.h b/source/io/slice.h
index f6115851c4c4c0637dcc262191c15e51cdcec81c..bcfef502343a23da7761f8b00caabda00705b789 100644 (file)
--- a/source/io/slice.h
+++ b/source/io/slice.h
@@ -16,7 +16,7 @@ its range.  If the offset of the underlying object is changed, the Slice will
 restore it before the next access.  This enables multiple Slices to be created
 on top of the same object.
 */
-class Slice: public Seekable
+class Slice: public Seekable, public sigc::trackable
 {
 private:
        Seekable &below;