How to make widgets inactive??

[Robert_Gasch/PeopleSoft peoplesoft com]

Hi,

I've been looking through the sample code, trying to find some
method of making a widget inactive. I haven't come up with anything
though, so here's my question:

How do I make a widget inactive? What I'm thinking of is that a menu
item (or button) can be active/selectable or inactive (not selectable). For
example, you should not be able to select 'Paste' unless you've already
'Copy'ied. Does Gtk support this? If anybody could fill me in on the
details,
I'd be much obliged ...

Thanks
--> Robert