Title and label Font size of color bar

When I try to change the font size of the title or text of a colorbar, nothing happens. For instance, in the following example:
`import numpy as np
from mayavi import mlab

x, y, z = np.ogrid[- .5:.5:200j, - .5:.5:200j, - .5:.5:200j]
r = np.sqrt(x ** 2 + y ** 2 + z ** 2)
L = - r ** 3 / 6 + 5. / 2 * r ** 2 - 10 * r + 6
Y = (x + y * 1j) ** 2 * z / r ** 3

Phi = L * Y * np.exp(- r) * r ** 2

mlab.figure(1, fgcolor=(1, 1, 1), bgcolor=(0, 0, 0))
src = mlab.pipeline.scalar_field(np.abs(Phi))
src.image_data.point_data.add_array(np.angle(Phi).T.ravel())
src.image_data.point_data.get_array(1).name = 'angle'
src.update()
src2 = mlab.pipeline.set_active_attribute(src,
point_scalars='scalar')
contour = mlab.pipeline.contour(src2)
contour2 = mlab.pipeline.set_active_attribute(contour,
point_scalars='angle')
mlab.pipeline.surface(contour2, colormap='hsv')

cb=mlab.colorbar(title='Phase', orientation='vertical', nb_labels=3)
cb.label_text_property.font_family = 'times'
cb.label_text_property.bold = 0
cb.label_text_property.font_size=24

mlab.show()

When Font_family and bold properties change, they affect the text in colorbar. However, this is not the case for the font size. Is it a bug or is there anything else that should be changed as well in order to change the font size in the colormap?