Bug 8808 Class folder: Must use create to add an existing folder
Build I20020129 "Add Folders..." does not show the project itself. I have to do the following trick to add an existing folder as class folder: Press "Create folder" Enter the name of the existing folder (hopfully it's in the project root :-) Voila BTW: I can't do this a second time - the UI tells me it already exists - which is OK. To be consistent with other dialogs "Create Folder" should always warn about existing projects.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/LibrariesWorkbookPage.java
for (int i= 0; i < res.length; i++) {
				IResource elem= (IResource) elements[i];
				res[i]= newCPLibraryElement(elem);
			}
			return res;
		}
		return null;		
	}
	
	private CPListElement[] chooseJarFiles() {
		Class[] acceptedClasses= new Class[] { IFile.class };
		ISelectionValidator validator= new TypedElementSelectionValidator(acceptedClasses, true);
		ViewerFilter filter= new ArchiveFileFilter(getUsedJARFiles());
		
		ILabelProvider lp= new WorkbenchLabelProvider();
		ITreeContentProvider cp= new WorkbenchContentProvider();
		ElementTreeSelectionDialog dialog= new ElementTreeSelectionDialog(getShell(), lp, cp);
		dialog.setValidator(validator);
		dialog.setTitle(NewWizardMessages.getString("LibrariesWorkbookPage.JARArchiveDialog.title")); 
		dialog.setMessage(NewWizardMessages.getString("LibrariesWorkbookPage.JARArchiveDialog.description")); 
		dialog.addFilter(filter);
		dialog.setInput(fWorkspaceRoot);
		dialog.setInitialSelection(fCurrJProject.getProject());		
		if (dialog.open() == dialog.OK) {
			Object[] elements= dialog.getResult();
			CPListElement[] res= new CPListElement[elements.length];
			for (int i= 0; i < res.length; i++) {
				IResource elem= (IResource)elements[i];
				res[i]= newCPLibraryElement(elem);
			}