The material of both balls is an insulator. Therefore, charges cannot travel inside the balls. However, the electric field of the charged ball induces the?polarization of molecules in the neutral ball and the neutral ball may be treated as a dipole. However, the electric field of the dipole is weaker than the field between the charged ball and the negative “end” of the neutral ball. Therefore, the field lines everywhere have the horizontal component from the charged ball to the neutral ball. The position of the balls and their threads does not change relatively to the initial one, as the balls attract each other.