[seahorse] GenerateSelect: allow iterating using the keyboard.

[Niels De Graef <nielsdg src gnome org>]

commit 539e5ee53bc4a90db7250cf331637b2396102b0c
Author: Niels De Graef <nielsdegraef gmail com>
Date:   Wed Aug 15 09:25:17 2018 +0200

    GenerateSelect: allow iterating using the keyboard.
    
    Commit f586e972 introduced as small regression that made it no longer
    possible to generate a new item using only the keyboard (i.e. <Ctrl>N
    followed by the arrow keys to choose which item).
    
    This commit re-allows this behavior.

 src/generate-select.vala | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
---
diff --git a/src/generate-select.vala b/src/generate-select.vala
index ce5bc159..723b198d 100644
--- a/src/generate-select.vala
+++ b/src/generate-select.vala
@@ -50,8 +50,12 @@ public class Seahorse.GenerateSelect : Gtk.Dialog {
             return ((Gtk.Action) a).label.collate(((Gtk.Action) b).label);
         });
 
-        // Select first item
-        this.generate_list.select_row(this.generate_list.get_row_at_index(0));
+        // Select first item (and grab focus, so user can use the keyboard immediately)
+        weak Gtk.ListBoxRow? row = this.generate_list.get_row_at_index(0);
+        if (row != null) {
+            this.generate_list.select_row(row);
+            row.grab_focus();
+        }
     }
 
     private Gtk.ListBoxRow on_create_row(GLib.Object item) {