diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/ui/actions/ExcludeFromBuildAction.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/ui/actions/ExcludeFromBuildAction.java
index 6a2916ec6d4..d5f7fdc4e9e 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/ui/actions/ExcludeFromBuildAction.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/ui/actions/ExcludeFromBuildAction.java
@@ -61,6 +61,7 @@ implements IWorkbenchWindowPulldownDelegate2, IObjectActionDelegate {
 
 	public void selectionChanged(IAction action, ISelection selection) {
 		objects = null;
+		cfgNames = null;
 		boolean cfgsOK = true;
 		
 		if (!selection.isEmpty()) {