Smarthome build failure

When I try to build smarthome from the latest master branch code, i get this error:

[ERROR] \smarthome\bundles\io\org.eclipse.smarthome.io.rest.sitemap\src\main\java\org\eclipse\smarthome\io\rest\sitemap\internal\PageChangeListener.java:[167]
[ERROR] event.label = itemUIRegistry.getLabel(w);
[ERROR] ^^^^^^^^
[ERROR] The method getLabel(Widget) from the type ItemUIRegistry refers to the missing type Widget