Shell shell = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getShell();
ElementListSelectionDialog dialog = new ElementListSelectionDialog(shell, new TypeLabelProvider());
dialog.setElements(types);
if (dialog.open() == Window.OK) {
Object[] result = dialog.getResult();
if (result != null && result.length == 1) {
this.type = (IType) result[0];