Is it possible to disable, fade or make a button inside a dialog unclickable in GTK?

Question

I have a dialog like this:

GtkWidget *dialog = gtk_dialog_new_with_buttons("Spell Checking", NULL, 0,
                                                GTK_STOCK_OK,
                                                GTK_RESPONSE_ACCEPT,
                                                GTK_STOCK_ADD,
                                                GTK_RESPONSE_APPLY,
                                                GTK_STOCK_CANCEL,
                                                GTK_RESPONSE_REJECT,
                                                NULL);

After adding all the other necessary elements it'll look like this:

What I want to do is to disable the OK button if the list of correct words is empty.

Of course, there are workarounds like creating a dialog:

• with OK when then the list is not empty
• without otherwise

Nevertheless, I would like to know if I can just disable/fade a buttoon and how.

Answer 1

GTK Widgets usually have a property Sensitive, when it's set to false, the widget grayed out, i.e. an user couldn't interact with it. There's a function for that purpose

void
gtk_widget_set_sensitive (GtkWidget *widget,
                          gboolean sensitive);

Also you could try to set it directly, like myButton->Sensitive = false.