Assuming that TPageControl remains the preferred way to organise a tabbed "notebook", I'm left with porting some older code and also trying to tune something I'm currently working on. I'm trying to stick to Lazarus 1.0, since particularly if I publish a program as being of use to non-Lazarus developers (e.g. an RJE workstation for the IBM mainframe crowd) I think that sticking to a major release is a benefit.

Given a TPageControl with several existing pages, how does one insert a page at a specified position rather than at the end?

Mark Morgan Lloyd wrote

Given a TPageControl with several existing pages, how does one insert a page at a specified position rather than at the end?

This function should do it:

uses ComCtrls;
function InsertAt(ExistingIndex: integer;
                   aPageControl: TPageControl): TTabSheet;
begin
   Result:=nil;
   if (ExistingIndex<0) or (ExistingIndex>aPageControl.PageCount-1) then
     Exit;
   Result:= aPageControl.AddTabSheet;
   if aPageControl.IndexOf(Result)  ExistingIndex then
     TNBPages(TCustomTabControl(aPageControl).Pages).Move(
                 aPageControl.IndexOf(Result), ExistingIndex);
end;

Thanks Howard, a slight variant of that is working. Any residual problems are my own doing :-)