The OS X application menu typically includes "Show All".
Unlike "Hide" and "Hide Others", there is not a standard action for "Show All". How is it programmed in Firemonkey?
Use the NSApplication.unhideAllApplications
function.
uses Macapi.AppKit;
procedure TForm1.ShowAllClick(Sender: TObject);
begin
TNSApplication.Wrap(TNSApplication.OCClass.sharedApplication).unhideAllApplications(nil);
end;