[five-or-more/arnaudb/issue-15-part-2] Fix changing theme.

[Arnaud B. <arnaudb src gnome org>]

commit 885b208e85bc036ce642ff6bb2feb1de9382f06e
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Thu Mar 19 12:07:05 2020 +0100

    Fix changing theme.
    
    Fixes #15 (for real).

 data/five-or-more-preferences.ui | 6 +++---
 src/preferences-dialog.vala      | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/data/five-or-more-preferences.ui b/data/five-or-more-preferences.ui
index 218d8cc..d87a35c 100644
--- a/data/five-or-more-preferences.ui
+++ b/data/five-or-more-preferences.ui
@@ -73,9 +73,9 @@
                     <property name="can_focus">False</property>
                     <property name="active">0</property>
                     <items>
-                      <item translatable="yes">balls</item>
-                      <item translatable="yes">shapes</item>
-                      <item translatable="yes">tango</item>
+                      <item translatable="yes" id="balls">balls</item>
+                      <item translatable="yes" id="shapes">shapes</item>
+                      <item translatable="yes" id="tango">tango</item>
                     </items>
                   </object>
                 </child>
diff --git a/src/preferences-dialog.vala b/src/preferences-dialog.vala
index c8f2ed7..30df00d 100644
--- a/src/preferences-dialog.vala
+++ b/src/preferences-dialog.vala
@@ -35,7 +35,7 @@ public class PreferencesDialog : Gtk.Dialog
     private void theme_set_cb (Gtk.ComboBox self)
     {
         var combo_box_text = self as Gtk.ComboBoxText;
-        var theme = combo_box_text.get_active_text ();
+        var theme = combo_box_text.get_active_id ();
         foreach (var t in ThemeRenderer.themes)
         {
             if (t.split (".")[0] == theme)