GtkTextMark right gravity

[Darryl Ross <djr dazco com au>]

I am trying to mark a section of text within a GtkTextBuffer and then 
later retrieve the text along with any changes made within the section. 
I have done the following:

    /* mark the section */
    start_mark = gtk_text_buffer_create_mark(buffer, NULL, &iter, TRUE);
    gtk_text_buffer_insert(buffer, &iter, "Hello, this is some text", -1);
    end_mark = gtk_text_buffer_create_mark(buffer, NULL, &iter, FALSE);
    /* here is some more text */   
    gtk_text_buffer_insert(buffer, &iter, "some more text", -1);

    /* retrieve the section */
    gtk_text_buffer_get_iter_at_mark(buffer, &start, start_mark);
    gtk_text_buffer_get_iter_at_mark(buffer, &end, end_mark);
    text = gtk_text_buffer_get_text(buffer, &start, &end, FALSE);

When I get the text the "some more text" text is included if end_mark 
has left gravity set to false, but it is not included if end_mark has 
left gravity set to true. I want end_mark to be right gravity as I want 
insertions at the end of the section to remain within the marked section.

Is this a bug or am I doing something wrong?

I have a small working test case if that helps.

-- 
Darryl Ross
Principal Consultant, Dazco Technology ABN: 58 829 870 455
+61 3 9734 2466 http://www.dazco.com.au