Background/foreground on disabled Tkinter.Entry

[Martyn Quick]

If I create a Tkinter.Entry widget, I can adjust the background and the
text colours, using the background and foreground options.  However, if
the state is "disabled", then this has no effect and it just appears as
grey on a light grey background.  E.g.,

Tkinter.Entry(root, foreground="black", background="white",
state="disabled").grid()

does not do what I expected.  What is the correct way to adjust the
foreground and background on disabled Entry widgets?

Thanks,

Martyn