Bug 64298 JAR files already in build path still shown when adding JARs.
When adding JARs to the Java build path in 3.0M9, the JAR's that are already added do not get filtered out anymore like with all previous builds (M8 and lower). Instead, the complete list of all available JARs is shown.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/LibrariesWorkbookPage.java
if (res != null && res.length > 0) {
			CPListElement curr= res[0];
			curr.setExported(elem.isExported());
			fLibrariesList.replaceElement(elem, curr);
		}		
			
	}
	private void libaryPageSelectionChanged(DialogField field) {
		List selElements= fLibrariesList.getSelectedElements();
		fLibrariesList.enableButton(IDX_EDIT, canEdit(selElements));
		fLibrariesList.enableButton(IDX_REMOVE, canRemove(selElements));
	}
	
	private boolean canEdit(List selElements) {
		if (selElements.size() != 1) {
			return false;
		}
		Object elem= selElements.get(0);
		if (elem instanceof CPListElement) {
			CPListElement curr= (CPListElement) elem;
			return !(curr.getResource() instanceof IFolder) && curr.getParentContainer() == null;
		}
		if (elem instanceof CPListElementAttribute) {
			return true;
		}
		return false;
	}
	
	private void libaryPageDialogFieldChanged(DialogField field) {
		if (fCurrJProject != null) {