Fix use of SettingsChangeNotifier

Change-Id: I41bfb0feaa5a2d479b8c1b8f7933e9f898cf2857
diff --git a/docmlet/org.eclipse.statet.docmlet.wikitext.ui/src/org/eclipse/statet/internal/docmlet/wikitext/ui/WikitextUIPlugin.java b/docmlet/org.eclipse.statet.docmlet.wikitext.ui/src/org/eclipse/statet/internal/docmlet/wikitext/ui/WikitextUIPlugin.java
index c2bc2eb..683db77 100644
--- a/docmlet/org.eclipse.statet.docmlet.wikitext.ui/src/org/eclipse/statet/internal/docmlet/wikitext/ui/WikitextUIPlugin.java
+++ b/docmlet/org.eclipse.statet.docmlet.wikitext.ui/src/org/eclipse/statet/internal/docmlet/wikitext/ui/WikitextUIPlugin.java
@@ -36,6 +36,7 @@
 import org.eclipse.ui.plugin.AbstractUIPlugin;
 import org.eclipse.ui.themes.IThemeManager;
 
+import org.eclipse.statet.jcommons.collections.ImCollections;
 import org.eclipse.statet.jcommons.lang.Disposable;
 
 import org.eclipse.statet.ecommons.preferences.PreferencesUtil;
@@ -207,8 +208,10 @@
 					
 					if (update) {
 						final Job job= PreferencesUtil.getSettingsChangeNotifier().getNotifyJob("mylyn", //$NON-NLS-1$
-								new String[] { WikitextEditingSettings.TEXTSTYLE_CONFIG_QUALIFIER } );
-						job.schedule(250);
+								ImCollections.newList(WikitextEditingSettings.TEXTSTYLE_CONFIG_QUALIFIER) );
+						if (job != null) {
+							job.schedule(250);
+						}
 					}
 				}
 			};