diff --git a/ui/org.eclipse.pde.core/src/org/eclipse/pde/internal/core/PluginModelManager.java b/ui/org.eclipse.pde.core/src/org/eclipse/pde/internal/core/PluginModelManager.java
index 66c7472ee9..389426f4e0 100644
--- a/ui/org.eclipse.pde.core/src/org/eclipse/pde/internal/core/PluginModelManager.java
+++ b/ui/org.eclipse.pde.core/src/org/eclipse/pde/internal/core/PluginModelManager.java
@@ -89,6 +89,11 @@ public UpdateClasspathsJob() {
 			setRule(ResourcesPlugin.getWorkspace().getRoot());
 		}
 
+		@Override
+		public boolean belongsTo(Object family) {
+			return family == PluginModelManager.class;
+		}
+
 		@Override
 		protected IStatus run(IProgressMonitor monitor) {
 			try {