gtk_text_view_get_iter_at_location and scrolling?

[martyn 2 russell bt com]

I use 
	gtk_text_view_get_iter_at_location(GTK_TEXT_VIEW(view), &iter, &x,
&y);
	
I then get the word at that location either side of the iter (up to
g_unichar_isspace(ch) == TRUE). 
This works fine *UNTIL* the buffer is large enough to need the scrollwindow.
At this point, the x and y still come back ok, but the text under the cursor
is the *SAME* text that the would be there if there scrollwindow was at the
top.  For some reason it is not refreshing.  To scroll down, I am using the
following method (to always scroll down on text input).

      	mark = gtk_text_buffer_create_mark(buffer, NULL, &iter, FALSE);
	gtk_text_view_scroll_mark_onscreen(textview, mark);
      	gtk_text_buffer_delete_mark(buffer, mark);¸

Here is the function callback for the motion notify event:

	gboolean on_textview_find_space(gunichar ch, gpointer user_data)
	{
	    if(g_unichar_isspace(ch) == TRUE)
		return TRUE;

	    return FALSE;
	}

	gboolean on_textview_motion_notify_event(GtkWidget *widget,
GdkEventMotion *event, gpointer user_data)
	{
	  gint x = 0;
	  gint y = 0;
	  GdkModifierType state = 0;
	  GdkWindow *window = NULL;

	  GtkTextIter iter;
	  GtkTextIter iter_start;
	  GtkTextIter iter_end;
  
	  gboolean found_start = FALSE;
	  gboolean found_end = FALSE;
	
	  gchar *buf = NULL;
	
	  if(event->is_hint)
	  {
	      window = gdk_window_get_pointer(event->window, &x, &y,
&state);
	  }
	  else
	  {
	      x = event->x;
	      y = event->y;
	      state = event->state;
	  }
	  
	  gtk_text_view_get_iter_at_location(textview, &iter, x, y);
	 
	  if(g_unichar_isspace(gtk_text_iter_get_char(&iter)) == TRUE)
	  {
	      g_message("iter is a space");
	      return TRUE;
	  }
	
	  iter_start = iter;
	  iter_end = iter;
	
	  /* search for next space */
	  found_start = gtk_text_iter_backward_find_char(&iter_start,
on_textview_find_space, NULL, NULL);
	  found_end = gtk_text_iter_forward_find_char(&iter_end,
on_textview_find_space, NULL, NULL);
	
	  if(found_start == FALSE && found_end == FALSE)
	  {
	      g_warning("on_textview_motion_notify_event: could not find
start and end space");
	      return TRUE;
	  }
	
	  if(gtk_text_iter_is_start(&iter_start) == FALSE)
	      gtk_text_iter_forward_char(&iter_start);
	  
	  if((buf = gtk_text_buffer_get_slice(buffer, &iter_start,
&iter_end, FALSE)) == NULL)
	  {
	      g_warning("on_textview_motion_notify_event: buf returned was
NULL");
	      return TRUE;
	  }
	  
	  g_message("word:'%s'", buf);
	  
	  if(supportIsURI(buf) != uriTypeUnknown)
	  {
	      GdkCursor *cursor = NULL;
	      cursor = gdk_cursor_new(GDK_HAND2);
	      gdk_window_set_cursor (event->window, cursor);
	      
	      /* clean up */
	      gdk_cursor_unref(cursor);
	  }  
	  else
	  {
	      /* return to parent window's cursor */
	      gdk_window_set_cursor(event->window, NULL);
	  }
	
	  /* clean up */
	  if(buf != NULL) g_free(buf);
	
	  return TRUE;
	}

Does the the textview need updating or refreshing in some way??
Also, this does the exact same thing if I do not scroll to the end and
instead insert the text (so that all new entries appear at the top).

I am using GTK 2.0.6 (as with RedHat 8.0).  

Regards,
Martyn