Since no one has given an answer yet, I'll chime in with confirmation. I see the same thing on Windows 10, even when not using Tk. I ended up spawning $^X, $pathToMyself because my perl association isn't working (new computer, apparently hadn't used my assoc yet), but I get the same results -- I have to hit ENTER to actual enter the new instance.

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

my $pathToMyself = $0;

local $, = "\n\t* ";
local $\ = $/;
print "\t".$^X, $0, @ARGV;

restartMe() unless @ARGV;

sub restartMe {
    print "Restarting $pathToMyself...\n";
    #exec( $^X, $pathToMyself ) or die "couldn't exec $pathToMyself: $
+!";
    #system(1, $^X, $pathToMyself, "don't Restart", "final" ); exit;
    #system(1, "cmd.exe", "/c", $^X, $pathToMyself, "final"); exit;
    exec("cmd.exe", "/c", $^X, $pathToMyself, "final") or die  "couldn
+'t exec $pathToMyself: $!";
}
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As you can see from my commented lines, I tried various combinations of exec and system, both with and without an explicit cmd.exe interpreter. I don't know what's going on, but I can definitely confirm it.

edit: fixed my association to be perl "%1" %*, so it would run without the cmd or $^X, but no change in behavior

    system(1, $pathToMyself, "don't Restart", "final" ); exit;
    #exec(  $pathToMyself, "final" ) or die "couldn't exec $pathToMyse
+lf: $!"; # can't exec ___: Exec format error -- because this runs wit
+hout the cmd.exe overhead, so it doesn't try the association for .pl 
+file
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