If your startup takes too long, you could either use a nice splash or just build the most important widgets before MainWindows and build the rest with one (or several) Tk::after...

  $mw->after(1, sub {&startup()});
  MainLoop;
[download]

Alternatively you can use waitvisibility, which tells the MainLoop to get the window up before proceeding past that point in the code.

So here is an example, using a simple sleep. However, this is where your REAL problem lies, how to get the STDOUT from your startup processes into your textbox. I've shown 2 subs. One is the standard insert with update, but that won't do you any good if some other program is writing to STDOUT. (Unless you use piped opens, IPC::Open3, etc)

But there is a trick for tieing STDOUT to the test widget, which I have shown. Now, you still need to update the text widget, which I have done in the simple loop. But in your real application startup, you will probably need to resort to a timer which updates the text widget on an interval.

#!/usr/bin/perl
use warnings;
use strict;
use Tk;

my $mw = tkinit;

my $textbox = &do_Toplevel();

#to wait until a $widget is visible, use waitVisibility: 
$mw->waitVisibility;

#your long startup code, telling it which textbox to display in  
#&startup($textbox); 
&startup1($textbox);

MainLoop;
################################################################# 
sub do_Toplevel {
    my $tl = $mw->Toplevel();
    $tl->title( "Early Status" );
    my $text = $tl->Scrolled('Text')->pack();
    $text->insert('end',"........startup messages.........\n");

    $tl->Button( -text    => "Close",
                 -command => sub { $tl->withdraw }
                )->pack;

 return $text;
}
##############################################################  
sub startup{
  my $textbox = shift;

  foreach my $num (1..10){
        $textbox->insert('end',"$num\n");
        $textbox->update;
        sleep 1;
        }
}

################################################################## 
sub startup1{
  my $textbox = shift;
  $|++;

  tie *STDOUT, 'Tk::Text', $textbox;

 #may need this to force repeated updates 
 # $mw->repeat(10,sub{  $textbox->update }); 


  foreach my $num (1..10){
        print "$num\n";   # printing to STDOUT 
        $textbox->update;
        sleep 1;
        }



}
__END__
[download]

It is my understanding that you can't do that until MainLoop anyway. So a solution could be to fork off an helping application, establish some form of IPC between it and your program and have it do the splash screen/scrolling status thing until the latter is finished.

Alternatively you may build a first, "presentation" GUI that does the scrolling status thing while collecting data from db access, then rebuild it with that data and update.

Whatever, be patient and I bet zentara will come up with a Nx (N a reasonably sized integer!) better solution and most probably actual example code!

I don't think there's a way to have a log window running, without having MainLoop started (which handles all windows activities).