FAQ weight inside category

I installed FAQ module and works good, but one thing I need help. I set up 2 Categories and (3 + 2 )guestions, but no way to arange questions order inside the category. when I select category, the square window supposed to show up all questions in this category is empty. I did try to adjust weight for each qustions but it does not work. If I do not enable Category and without adding Vocabulary from Taxonomy, all questions will show up here and easy to adjust order. what steps have I missed?