Colors & Appearances Menu Missing

Hello,

I have an assembly in which some of the parts have reverted to default colour, whilst others have not. When I try to modify the colour of any part, I click on the View, Color & Appearance menu and nothing happens.

I tried a different assembly, after re-booting and the same occurs.

Where has my Color & Appearance menu gone?

WF4 m220 64 bit

Ilink 3.4 m062

Thanks,

John