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/LibrariesWorkbookPage.java
public void init(IJavaProject jproject) {
		fCurrJProject= jproject;
		updateLibrariesList();
	}
	
	private boolean isLibraryKind(int kind) {
		return kind == IClasspathEntry.CPE_LIBRARY || kind == IClasspathEntry.CPE_VARIABLE || kind == IClasspathEntry.CPE_CONTAINER;
	}
	
	private void updateLibrariesList() {
		List cpelements= fClassPathList.getElements();
		List libelements= new ArrayList(cpelements.size());
		
		int nElements= cpelements.size();
		for (int i= 0; i < nElements; i++) {
			CPListElement cpe= (CPListElement)cpelements.get(i);
			if (isLibraryKind(cpe.getEntryKind())) {
				libelements.add(cpe);
			}
		}
		fLibrariesList.setElements(libelements);
	}		
		
	
	
	public Control getControl(Composite parent) {
		PixelConverter converter= new PixelConverter(parent);
		
		Composite composite= new Composite(parent, SWT.NONE);