[Paraview] transparency of a surface

[Shigenobu Hirose]

Hi all,

I want to change the transparency of a surface colored by some scalar
value, but "Opacity" in the color scale editor is *gray* and cannot be
changed. ("Scalar Value" there can be changed.)

I'm using Paraview 3.2.1, Mac OS X PPC.

Could someone tell me what is wrong?

Thank you.
Shigenobu