private void doAddFolder() {
ElementTreeSelectionDialog dialog = new ElementTreeSelectionDialog(getSection().getShell(), new WorkbenchLabelProvider(), new WorkbenchContentProvider());
dialog.setAllowMultiple(true);
dialog.setTitle("Class Folder Selection");
dialog.setMessage("Select Class Folders to add to the Classpath.");
dialog.addFilter(new ClassFolderFilter());
IResource resource = getInputResource();
dialog.setInput(resource.getProject());
if (dialog.open() == Window.OK) {