I use Xubuntu 13.1 to develop some applications with gtk in c++ using libgtk-3-dev. I use message dialog boxes for error messages, like this
dialog = gtk_message_dialog_new(GTK_WINDOW(mainWindow), GTK_DIALOG_DESTROY_WITH_PARENT, GTK_MESSAGE_WARNING, GTK_BUTTONS_CLOSE, "error");
This displays the error as expected, and there is a "warning icon" with a large "!" in the box. But this warning icon is gray only, while in literature it is always red. Also in many applications, evidently using the same dialog box, it is red also. Only in newly written programs in Xubuntu 13.1 it is gray. Changing themes has no effect on this behavior at all. It only changes the gray tones, but does not bring color in. Why is this so, and how can I change it?