How to find code that causes a 'deprecated' warning?

[Peter Otten]

Chris Green wrote:

> I am getting the following warning from a program I have just
> converted from gtk 2 to gtk 3 :-
> 
> (abook:58240): Gtk-WARNING **: 12:01:58.064: Theme parsing error:
> gtk.css:66:28: The :prelight pseudo-class is deprecated. Use :hover
> instead.
> 
> How do I find what is causing the warning?  I'm not using the prelight
> pseudo-class directly in my code anywhere.

>From reading the message I would guess that the culprit is the file gtk.css, 
line 66 specifically ;)