For functions using _gtk_text_buffer_get_line_log_attrs():
- gtk_text_buffer_backspace()
- some gtk_text_iter functions (word/sentence/cursor boundaries)
As the FIXME comments show, there is a bug with
gtk_text_iter_is_cursor_position() for an empty last line.
https://bugzilla.gnome.org/show_bug.cgi?id=156164
It tests gtk_text_buffer_paste_clipboard(),
gtk_text_buffer_copy_clipboard() and gtk_text_buffer_cut_clipboard() in
various situations, including when GtkTextTags are applied to the
selection.
The last test didn't pass.
https://bugzilla.gnome.org/show_bug.cgi?id=339539
