Checkbox and Style

["Jean-Christophe Berthon" <Jean-Christophe Berthon cgey com>]

    Hello,

        I have another problem which is how to change the state of a
checkbox to "Partially Checked".

Explanation:

The user select a column. Each data in this column can be TRUE or FALSE. So
if a column contain only TRUE rows, then a checkbox should be "Checked", if
it contains only FALSE then it should be "Unchecked" and finally if there is
a mix of TRUE and FALSE the checkbox should be "Partialy Checked".
I've seen that behaviour under a few application, where when it was checked,
there was a black V drawn on the button of the checkbox, when unchecked the
V was cleared, and when partially cheked, the V was grey-ish.

    I've tryed using the fg fields of the Style of the checkbox, but it had
no effect! It seems that Gtk is using a picture to draw the checkbox. How
can I do it?

    Thank you for any help,


Best regards,
---
Jean-Christophe Berthon