Bug 4240 Can't edit class path entry (1GKEPIF)
There is no way to edit an existing entry for a library on the Java Build Path project properties page (other than editing the .classpath file directly). NOTES: EG (9/22/2001 11:42:11 AM) this is particularly annoying for variables. we should have an Edit button when a variable is selected.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/SourceContainerWorkbookPage.java
null,
			 NewWizardMessages.getString("SourceContainerWorkbookPage.folders.remove.button") 
		};
		removeIndex= 3;
		
		fFoldersList= new ListDialogField(adapter, buttonLabels, new CPListLabelProvider());
		fFoldersList.setDialogFieldListener(adapter);
		fFoldersList.setLabelText(NewWizardMessages.getString("SourceContainerWorkbookPage.folders.label")); 
		fFoldersList.setRemoveButtonIndex(removeIndex);
		
		fFoldersList.setViewerSorter(new CPListElementSorter());
		
		fFolderRadioButton.setSelection(true);
		fProjectRadioButton.setSelection(false);
		fFolderRadioButton.attachDialogField(fFoldersList);	
	}
	
	public void init(IJavaProject jproject) {
		fCurrJProject= jproject;
		fProjPath= fCurrJProject.getProject().getFullPath();	
		updateFoldersList();
	}
	
	private void updateFoldersList() {	
		fIsProjSelected= false;
		List srcelements= new ArrayList(fClassPathList.getSize());
		
		List cpelements= fClassPathList.getElements();
		for (int i= 0; i < cpelements.size(); i++) {
			CPListElement cpe= (CPListElement)cpelements.get(i);