--- a/actions.cc
+++ b/actions.cc
@@ -51,10 +51,11 @@
 	context->set_icon(pb, pb->get_width(), pb->get_height());
 }
 
-bool negate(bool b) { return !b; }
-
 TreeViewMulti::TreeViewMulti() : Gtk::TreeView(), pending(false) {
-	get_selection()->set_select_function(sigc::group(&negate, sigc::ref(pending)));
+	get_selection()->set_select_function(
+		[this](Glib::RefPtr<Gtk::TreeModel> const&, Gtk::TreeModel::Path const&, bool) {
+			return !pending;
+		});
 }
 
 enum Type { COMMAND, KEY, TEXT, SCROLL, IGNORE, BUTTON, MISC };