This paper studies a user interface innovation in digital textbooks on tablet PCs which supports a new learning style in user active learning. The style consists of handwritten annotations on digital textbooks and automatic question generations based on users' markings. First we discuss current problems and issues for digital textbook markings to support user active learning and then propose a learning support framework and implementation methods. We then present experimental results from our user study about annotation and markings on tablet PCs. Our study shows the proposed learning support framework and the innovative learning style is feasible.