Studying students' performance in learning differentiability is essential since it requires them to perform proceptual thinking. This case study research investigates students' proceptual thinking outcomes in learning the differentiability concept using Desmos Classroom Activities (DCA) based on the Three Worlds of Mathematics (TWM) framework. In this study, DCA facilitates students' learning of differentiability with a sensible approach and exposes them to the graphical exploration of non-differentiable functions. Students succeeded in concluding that continuity does not imply differentiability. With its graphical, computational, and symbol manipulation capabilities, DCA has facilitated students to perform proceptual thinking in learning differentiability through a richer learning experience. Many students (76%) could perform at the procept level when solving the differentiability problem. Also, twenty-two students (about 88%) had no limitations in the graphical representation. The result of this study confirms that DCA based on the TWM as a generic organizer can contribute to students' proceptual thinking outcomes in learning differentiability.