Bug 120544 [build path] Editing external source folder does not persist
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/BuildPathsBlock.java
fPageContainer= pageContainer;
		fWorkspaceRoot= JavaPlugin.getWorkspace().getRoot();
		fContext= context;
		fUseNewPage= useNewPage;
		
		fPageIndex= pageToShow;
		
		fSourceContainerPage= null;
		fLibrariesPage= null;
		fProjectsPage= null;
		fCurrPage= null;
        fRunnableContext= runnableContext;
				
		BuildPathAdapter adapter= new BuildPathAdapter();			
	
		String[] buttonLabels= new String[] {
			NewWizardMessages.BuildPathsBlock_classpath_up_button, 
			NewWizardMessages.BuildPathsBlock_classpath_down_button, 
			 null,
			NewWizardMessages.BuildPathsBlock_classpath_checkall_button, 
			NewWizardMessages.BuildPathsBlock_classpath_uncheckall_button
		
		};
		
		fClassPathList= new CheckedListDialogField(null, buttonLabels, new CPListLabelProvider());
		fClassPathList.setDialogFieldListener(adapter);
		fClassPathList.setLabelText(NewWizardMessages.BuildPathsBlock_classpath_label);  
		fClassPathList.setUpButtonIndex(0);
		fClassPathList.setDownButtonIndex(1);
		fClassPathList.setCheckAllButtonIndex(3);