Index: GtkCellRenderer.xs
===================================================================
--- GtkCellRenderer.xs	(revision 2095)
+++ GtkCellRenderer.xs	(working copy)
@@ -272,6 +272,53 @@
 		sv = POPs;
 		if (gperl_sv_is_defined (sv)) {
 			editable = SvGtkCellEditable (sv);
+
+#if GLIB_CHECK_VERSION (2, 10, 0)
+			/* (*start_editing)() is basically a constructor and
+			 * as such should return an object with a floating
+			 * reference for the caller to take over.
+			 *
+			 * For GtkTreeView and GtkIconView for example that
+			 * ref is sunk when gtk_tree_view_put() or
+			 * gtk_icon_view_put() call gtk_widget_set_parent()
+			 * to add "editable" as one of their container
+			 * children.  (Eventually to be dereffed in the
+			 * usual way by gtk_container_remove() from
+			 * gtk_tree_view_remove_widget() or
+			 * gtk_icon_view_remove_widget() at the end of
+			 * editing.)
+			 *
+			 * Perl code constructors like Gtk2::Foo->new or
+			 * Glib::Object->new sink any initial floating
+			 * reference when making the wrapper (either if
+			 * constructing in the START_EDITING code or from
+			 * something made or wrapped previously).  So must
+			 * explicitly add a floating ref for GtkTreeView etc
+			 * to take over.
+			 *
+			 * If START_EDITING code gives a new object in "sv"
+			 * and it's used nowhere else then FREETMPS below
+			 * will SvREFCNT_dec it to zero and send it to the
+			 * usual Glib::Object::DESTROY.  If there wasn't a
+			 * floating ref added here on the GObject then that
+			 * GObject would be destroyed before we ever got to
+			 * return it.  With the extra floating ref the
+			 * wrapper converts to undead (ie. unused from perl
+			 * for the time being) and the GObject has a
+			 * refcount of 1 and the floating flag set.
+			 *
+			 * It's conceivable there could be a floating ref
+			 * already at this point.  That was the case in the
+			 * past from chained-up perl SUPER::START_EDITING
+			 * for instance.  Though it's abnormal let's assume
+			 * any floating ref here is meant for the caller to
+			 * take over and therefore should be left unchanged.
+			 */
+			if (! g_object_is_floating (editable)) {
+				g_object_ref (editable);
+				g_object_force_floating (G_OBJECT (editable));
+			}
+#else
 			/* if the object returned here was newly created by
 			 * the called code, then the wrapper (pointed to by
 			 * sv) is the owner of the object.  if there are no
@@ -288,6 +335,7 @@
 			    SvREFCNT (SvRV (sv)) == 1) {
 				SvREFCNT_inc (SvRV (sv));
 			}
+#endif
 		} else {
 			editable = NULL;
 		}