Resolves: fdo#72989 color buttons not disabled in readonly docs

we we not calling EnableItem for most of the color options so it didn't get
disabled in readonly mode, and anyway it was using nSID as the itemid rather
than getId() so even if EnableItem was called it didn't have an effect.

Change-Id: Ia7b55d78d369a79d3e45c8407f859d47fceac753