After annealing a continuous SiO2 film on the (001) surface of TiO2, the film dewets and then spreads to form a complex pattern. The final droplet morphology displays a densely branching morphology similar to those seen in computer-simulated models. It is proposed that Bénard-Marangoni convection cells form within the film before dewetting occurs. The formation of Bénard-Marangoni convection cells prior to dewetting results in the uniform size and spacing of the droplets on the surface. These convection cells form at temperature when the TiO2 substrate dissolves into the SiO2 thin film. The change in composition results in regions of differing surface tensions and therefore leads to the formation of the convection cells.