[gnome-music/wip/jfelder/core-restore-player-validation: 4/6] songsview: Explain why iter_to_clean is necessary

[Jean Felder <jfelder src gnome org>]

commit bbb210c1556efa39a34f0a4b286fbcd1930229d4
Author: Jean Felder <jfelder src gnome org>
Date:   Sun Jul 14 16:26:25 2019 +0200

    songsview: Explain why iter_to_clean is necessary
    
    This is a bug in Gtk. The pixel cache in GtkTreeView does not work
    correctly.

 gnomemusic/views/songsview.py | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/gnomemusic/views/songsview.py b/gnomemusic/views/songsview.py
index 39508b1f..7b238091 100644
--- a/gnomemusic/views/songsview.py
+++ b/gnomemusic/views/songsview.py
@@ -217,6 +217,8 @@ class SongsView(BaseView):
 
         :param Player player: The main player object
         """
+        # iter_to_clean is necessary because of a bug in GtkTreeView
+        # See https://gitlab.gnome.org/GNOME/gtk/issues/503
         if self._iter_to_clean:
             self._view.props.model[self._iter_to_clean][9] = False