Index: /trunk/test/unit/org/openstreetmap/josm/gui/preferences/PreferencesTestUtils.java
===================================================================
--- /trunk/test/unit/org/openstreetmap/josm/gui/preferences/PreferencesTestUtils.java	(revision 9632)
+++ /trunk/test/unit/org/openstreetmap/josm/gui/preferences/PreferencesTestUtils.java	(revision 9633)
@@ -19,4 +19,15 @@
      */
     public static void testPreferenceSettingAddGui(PreferenceSettingFactory factory, Class<? extends DefaultTabPreferenceSetting> parentClass) {
+        testPreferenceSettingAddGui(factory, parentClass, 1);
+    }
+
+    /**
+     * Generic test for {@link PreferenceSetting#addGui(PreferenceTabbedPane)}.
+     * @param factory setting factory to test
+     * @param parentClass optional parent setting, can be {@code null}
+     * @param increment expected tab number increment
+     */
+    public static void testPreferenceSettingAddGui(PreferenceSettingFactory factory, Class<? extends DefaultTabPreferenceSetting> parentClass,
+            int increment) {
         PreferenceSetting setting = factory.createPreferenceSetting();
         PreferenceTabbedPane tabPane = new PreferenceTabbedPane();
@@ -25,5 +36,5 @@
         setting.addGui(tabPane);
         if (parentClass != null) {
-            assertEquals(tabs + 1, tabPane.getSetting(parentClass).getTabPane().getTabCount());
+            assertEquals(tabs + increment, tabPane.getSetting(parentClass).getTabPane().getTabCount());
             assertEquals(tabPane.getSetting(parentClass), ((SubPreferenceSetting) setting).getTabPreferenceSetting(tabPane));
         }
Index: /trunk/test/unit/org/openstreetmap/josm/gui/preferences/display/DrawingPreferenceTest.java
===================================================================
--- /trunk/test/unit/org/openstreetmap/josm/gui/preferences/display/DrawingPreferenceTest.java	(revision 9632)
+++ /trunk/test/unit/org/openstreetmap/josm/gui/preferences/display/DrawingPreferenceTest.java	(revision 9633)
@@ -35,5 +35,5 @@
     @Test
     public void testAddGui() {
-        PreferencesTestUtils.testPreferenceSettingAddGui(new DrawingPreference.Factory(), DisplayPreference.class);
+        PreferencesTestUtils.testPreferenceSettingAddGui(new DrawingPreference.Factory(), DisplayPreference.class, 2);
     }
 }
Index: /trunk/test/unit/org/openstreetmap/josm/gui/preferences/display/LanguagePreferenceTest.java
===================================================================
--- /trunk/test/unit/org/openstreetmap/josm/gui/preferences/display/LanguagePreferenceTest.java	(revision 9632)
+++ /trunk/test/unit/org/openstreetmap/josm/gui/preferences/display/LanguagePreferenceTest.java	(revision 9633)
@@ -35,5 +35,5 @@
     @Test
     public void testAddGui() {
-        PreferencesTestUtils.testPreferenceSettingAddGui(new LanguagePreference.Factory(), DisplayPreference.class);
+        PreferencesTestUtils.testPreferenceSettingAddGui(new LanguagePreference.Factory(), null);
     }
 }