Bug 135050 - Don't set the indexer id when it isn't set in the project preferences. Only set it under UI when the workspace isn't locked.

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/PDOMManager.java

@@ -142,8 +142,6 @@ public class PDOMManager implements IPDOMManager, IElementChangedListener {
     		if (indexerId == null)
     			// make it the default
     			indexerId = getDefaultIndexerId();
-    		
-    		setIndexerId(project, indexerId);
     	}
   	    return indexerId;
     }