use strict;
use Tk;
use Tk::BrowseEntry;

my $top = new MainWindow( -title => "BrowseEntry 2");
main( $top );
$top->geometry("90x90");
MainLoop();

sub main {
    my( $top ) = @_;
    my @countries = qw( America Belize Canada Denmark Egypt Fruitopia );
    my $f = $top->Frame(-bg => "blue")->pack( qw/-side left / );
    my $oh = $f->BrowseEntry( -bg => "green",
                                           -choices => \@countries)->pack;
    my $be = $f->BrowseEntry( -state => "readonly", bg => "green",
                                           -choices => \@countries,
                                  )->pack;
}

       ...,
       ($Tk::VERSION >= 804 
        ? (-disabledbackground => "green",
            -disabledforeground => "black",
           )
        : ()
       ),
       ...

my $be = $f->BrowseEntry( -state => "readonly", bg => "green",
  -choices => \@countries,
  ($Tk::VERSION >= 804 ? (-disabledbackground => "green",
                          -disabledforeground => "black",
                         )
                       : ()
  ),
)->pack;