APEX: Active Tabs Based on Page Groups

Recently someone asked me: "How did you do that? When I include an APEX page in a Page Group, the correct tab is automatically highlighted"
When I setup an application, I usually use Dimitri Gielis' method, so instead of using "real tabs", I use a List and display that list as Tabs.
For each of the "Tabs", I also create Page Groups, just to keep things organized.

Each of the List Entries will have a PL/SQL Expression for "List Entry Current for Pages Type" based on the Page Group that the "Tab" should be active.

The function queries the APEX Repository, and more specifically APEX_APPLICATION_PAGES.

function page_in_group(
         p_app_id     in number ,
         p_page_id    in number ,
         p_page_group in varchar2 )
   return boolean
is
   l_retval boolean;
   l_dummy  number;
begin
   begin
       select 1
         into l_dummy
         from apex_application_pages
        where application_id = p_app_id
          and page_id            = p_page_id
          and page_group         = p_page_group;
       l_retval := l_dummy = 1;
   exception
      when no_data_found then
         l_retval := false;
   end;
   return l_retval;
end page_in_group;

Placing the Page in the correct Page Group will now "automatically" highlight the correct "tab".