Deactivate tabs in GtkNotebook

[Ken Siersma <siersmak ekkinc com>]

Hi list,

I'd like to create a notebook that has 5 different pages in it, but the
data to be displayed in the later pages depend on the first page.  I
want the tabs for all pages to be shown in the notebook, to indicate to
the user that they need to step through the last 4 too, but I don't want
them to be able to select those tabs until they complete the form in the
first page. 

So, I figured I could create all 5 pages and just deactivate the last 4
somehow.  The way I am trying to do it is to set the sensitivity of the
last 4 tab label widgets to FALSE, which gives the appearance that those
tabs cannot be selected.  Then, I've setup a switch-page function for
this notebook which checks if the tab is not sensitive, and if so it
sets the current page in the notebook to 0:

void switch_page(GtkNotebook *nb, GtkNotebookPage *pg, guint page_new,
gpointer data)
{
   int page_cur;
   GtkWidget *label;
   GtkWidget *child;
  
   page_cur = gtk_notebook_get_current_page(nb);    
 
   child = gtk_notebook_get_nth_page(nb, page_new); /* Get child widget
of new page */
   label = gtk_notebook_get_tab_label(nb, child); /* Get label for new
page */
  
   if(!GTK_WIDGET_IS_SENSITIVE(label))
   {
      printf(" !! Not sensitive !!\n");
      gtk_notebook_set_current_page(nb, 0);
   }
}

The program outputs the "!! Not sensitive !!", but it still switches to
page_new and shows the (empty) contents of that page.

Any ideas?
-Ken