I heard that urinating whilst standing is not permissible in Islam, so I left that practice. However I have a little problem when preparing to do wudu. When I urinate while not standing in toilets, I rarely get all my urine out. This causes me to sometimes break my prayer to redo wudu again because I feel that urine drops are coming out. Maybe this is because of a habit, but I want know if it is really forbidden.