[glom/gtkmm4v4] gtkmm4: DbAddDel: Don't use removed GtkTreeView::horizontal-separator property.

[Murray Cumming <murrayc src gnome org>]

commit 36901c348014310a5701a9778d8637455a9c68ea
Author: Murray Cumming <murrayc murrayc com>
Date:   Thu Apr 20 10:53:00 2017 +0200

    gtkmm4: DbAddDel: Don't use removed GtkTreeView::horizontal-separator property.
    
    This was removed from GTK+:
    https://git.gnome.org/browse/gtk+/commit/gtk/gtktreeview.c?id=5e06701f53c0c655c992583ad83dec717ac35a8f

 glom/mode_data/db_adddel/db_adddel.cc |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/glom/mode_data/db_adddel/db_adddel.cc b/glom/mode_data/db_adddel/db_adddel.cc
index 9135499..5924a36 100644
--- a/glom/mode_data/db_adddel/db_adddel.cc
+++ b/glom/mode_data/db_adddel/db_adddel.cc
@@ -666,7 +666,7 @@ void DbAddDel::construct_specified_columns()
     // have to take into account the xpad property of the cell renderer and
     // the spacing property of the treeviewcolumn.
     int horizontal_separator = 0;
-    m_tree_view.get_style_property("horizontal-separator", horizontal_separator);
+    //m_tree_view.get_style_property("horizontal-separator", horizontal_separator);
     const int button_width = requistion_min.width + horizontal_separator*2;
     if(button_width > 0) //Otherwise an assertion fails.
       m_treeviewcolumn_button->set_fixed_width(button_width);