GtkCombo::set_case_sensitive
void set_case_sensitive(bool val);
set_case_sensitve, if set
to true, will not match items that are dissimilar
with regard to case -in other words, Cat is not
the same thing as cat.
The default behaviour is that a string in the combo's entry box that is
accurate in all the ways other than case will be altered to match the
list version of that string.
