Thanks for all those info. Now the code is somewhat better. Is it possible to set up Editor Styles as Padre or Color Schemes as Geany, how?. Code is attached with new changes by me.

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


######################################################################
+#######
##
## Based on a very early version of Padre...
## The first version that could already save files.
##
## Copyright:   (c) The Padre development team
## Licence:     This program is free software; you can redistribute it
+ and/or
##              modify it under the same terms as Perl itself
######################################################################
+#######

# see package main at the bottom of the file


#####################
package Demo::Editor;
use strict;
use warnings FATAL => 'all';

use base 'Wx::App';

sub OnInit {
    my $frame = Demo::Frame->new;
    $frame->Show(1);
}

#####################
package Demo::Frame;
use strict;
use warnings FATAL => 'all';


use Wx ':everything';
use Wx::Event ':everything';
use Wx::Scintilla ();

use File::Spec::Functions qw(catfile);
use File::Basename qw(basename);

use base 'Wx::Frame';

our $VERSION = '0.01';
my $default_dir = "";
my $editor;
our $nb;
my %nb;
my $search_term = '';


sub new {
    my ($class) = @_;

    my $self = $class->SUPER::new(
        undef,
        -1,
        'Editor ',
        [ -1,  -1 ],
        [ 750, 700 ],
    );
    $nb = Wx::Notebook->new(
        $self, -1, wxDefaultPosition, wxDefaultSize,
        wxNO_FULL_REPAINT_ON_RESIZE | wxCLIP_CHILDREN
    );
   
    $self->_create_menu_bar;

    $self->setup_editor;
    return $self;
}

sub _create_menu_bar {
    my ($self) = @_;

    my $bar  = Wx::MenuBar->new;
    my $file = Wx::Menu->new;
    $file->Append( wxID_OPEN,   "&Open" );
    $file->Append( wxID_SAVE,   "&Save" );
    $file->Append( wxID_SAVEAS, "Save &As" );
    $file->Append( wxID_CLOSE,  "&Close" );
    $file->Append( wxID_EXIT,   "E&xit" );

    my $edit = Wx::Menu->new;
    $edit->Append( wxID_FIND, "&Find" );
    $edit->Append( 998,       "&Setup" );

    my $help = Wx::Menu->new;
    $help->Append( wxID_ABOUT, "&About..." );

    $bar->Append( $file, "&File" );
    $bar->Append( $edit, "&Edit" );
    $bar->Append( $help, "&Help" );

    $self->SetMenuBar($bar);

    EVT_CLOSE( $self, \&on_close_window );
    EVT_MENU( $self, wxID_OPEN, sub { on_open( $self, @_ ) } );
    EVT_MENU( $self, wxID_SAVE, sub { on_save( $self, @_ ) } );
    EVT_MENU( $self, wxID_SAVEAS, sub { on_save_as( $self, @_ ) } );
    EVT_MENU( $self, wxID_CLOSE, sub { on_close( $self, @_ ) } );
    EVT_MENU( $self, 998, sub { on_setup( $self, @_ ) } );
    EVT_MENU( $self, wxID_FIND, sub { on_find( $self, @_ ) } );
    EVT_MENU( $self, wxID_EXIT, \&on_exit );
    EVT_MENU( $self, wxID_ABOUT, \&on_about );

    return;
}

sub on_exit {
    my ($self) = @_;
    foreach my $id ( keys %nb ) {
        if ( _buffer_changed($id) ) {
            Wx::MessageBox( "One of the files is still not saved", "xx
+", wxOK | wxCENTRE, $self );
            return;
        }
    }

    $self->Close;
}

sub setup_editor {
    my ( $self, $file ) = @_;

    my $editor = Demo::Panel->new($nb);

    my $title   = "Unsaved Document 1";
    my $content = '';
    if ($file) {
        if ( open my $in, '<', $file ) {
            local $/ = undef;
            $content = <$in>;
        }
        $title = basename($file);
        $editor->SetText($content);
    }
    $nb->AddPage( $editor, $title, 1 );
    $nb{ $nb->GetSelection } = {
        filename => $file,
        content  => $content,
    };
    
    return;
}

sub on_close_window {
    my ( $self, $event ) = @_;
    $event->Skip;
}

sub on_open {
    my ($self) = @_;

    #Wx::MessageBox( "Not implemented yet. Should open a file selector
+", wxOK|wxCENTRE, $self );
    my $dialog = Wx::FileDialog->new( $self, "Open file", $default_dir
+, "", "*.*", wxFD_OPEN );
    if ( $dialog->ShowModal == wxID_CANCEL ) {

        #print "Cancel\n";
        return;
    }
    my $filename = $dialog->GetFilename;

    #print "OK $filename\n";
    $default_dir = $dialog->GetDirectory;

    my $file = catfile( $default_dir, $filename );

    $self->setup_editor($file);

    return;
}

sub on_save_as {
    my ($self) = @_;

    my $id = $nb->GetSelection;
    while (1) {
        my $dialog = Wx::FileDialog->new( $self, "Save file as...", $d
+efault_dir, "", "*.*", wxFD_SAVE );
        if ( $dialog->ShowModal == wxID_CANCEL ) {

            #print "Cancel\n";
            return;
        }
        my $filename = $dialog->GetFilename;

        #print "OK $filename\n";
        $default_dir = $dialog->GetDirectory;

        my $path = catfile( $default_dir, $filename );
        if ( -e $path ) {
            my $res = Wx::MessageBox( "File already exists. Overwrite 
+it?", 3, $self );
            if ( $res == 2 ) {
                $nb{$id}{filename} = $path;
                last;
            }
        } else {
            $nb{$id}{filename} = $path;
            last;
        }
    }
    $self->_save_buffer($id);
    return;
}

sub on_save {
    my ($self) = @_;
    my $id = $nb->GetSelection;
    return if not _buffer_changed($id);

    if ( $nb{$id}{filename} ) {
        $self->_save_buffer($id);
    } else {
        $self->on_save_as;
    }
    return;
}

sub _save_buffer {
    my ( $self, $id ) = @_;

    my $page    = $nb->GetPage($id);
    my $content = $page->GetText;
    if ( open my $out, '>', $nb{$id}{filename} ) {
        print $out $content;
    }
    $nb{$id}{content} = $content;

    return;
}

sub on_close {
    my ($self) = @_;

    my $id = $nb->GetSelection;
    if ( _buffer_changed($id) ) {
        Wx::MessageBox( "File changed.", wxOK | wxCENTRE, $self );
    }

    return;
}

sub _buffer_changed {
    my ($id) = @_;

    my $page    = $nb->GetPage($id);
    my $content = $page->GetText;
    return $content ne $nb{$id}{content};
}

sub on_setup {
    my ($self) = @_;
    Wx::MessageBox( "Not implemented yet.", wxOK | wxCENTRE, $self );
}


sub on_find {
    my ($self) = @_;

    my $dialog = Wx::TextEntryDialog->new( $self, "", "Type in search 
+term", $search_term );
    if ( $dialog->ShowModal == wxID_CANCEL ) {
        return;
    }
    $search_term = $dialog->GetValue;
    $dialog->Destroy;
    return if not defined $search_term or $search_term eq '';

    print "$search_term\n";
    return;
}


sub on_about {
    my ($self) = @_;

    Wx::MessageBox(
        "wxPerl editor, (c) 2008 Gabor Szabo\n" . "wxPerl editor $VERS
+ION, " . wxVERSION_STRING,
        "About wxPerl editor", wxOK | wxCENTRE, $self
    );
}

#####################

package Demo::Panel;

use strict;
use warnings FATAL => 'all';
use Wx::Scintilla;
use base 'Wx::Scintilla::TextCtrl';
use Wx ':everything';
use Wx::Event ':everything';

our $VERSION = '0.01';

sub new {
    my ( $class, $parent ) = @_;
    my $self = $class->SUPER::new( $parent, -1, [ -1, -1 ], [ 750, 700
+ ]); # TODO get the numbers from the frame?

    my $font = Wx::Font->new( 10, wxTELETYPE, wxNORMAL, wxNORMAL );

    $self->SetFont($font);

    $self->StyleSetFont( Wx::Scintilla::STYLE_DEFAULT, $font );
    $self->StyleClearAll;

    $self->StyleSetForeground( 0,  Wx::Colour->new( 0x00, 0x00, 0x7f )
+ );
    $self->StyleSetForeground( 1,  Wx::Colour->new( 0xff, 0x00, 0x00 )
+ );
    $self->StyleSetForeground( 2,  Wx::Colour->new( 0x00, 0x7f, 0x00 )
+ );
    $self->StyleSetForeground( 3,  Wx::Colour->new( 0x7f, 0x7f, 0x7f )
+ );
    $self->StyleSetForeground( 4,  Wx::Colour->new( 0x00, 0x7f, 0x7f )
+ );
    $self->StyleSetForeground( 5,  Wx::Colour->new( 0x00, 0x00, 0x7f )
+ );
    $self->StyleSetForeground( 6,  Wx::Colour->new( 0xff, 0x7f, 0x00 )
+ );
    $self->StyleSetForeground( 7,  Wx::Colour->new( 0x7f, 0x00, 0x7f )
+ );
    $self->StyleSetForeground( 8,  Wx::Colour->new( 0x00, 0x00, 0x00 )
+ );
    $self->StyleSetForeground( 9,  Wx::Colour->new( 0x7f, 0x7f, 0x7f )
+ );
    $self->StyleSetForeground( 10, Wx::Colour->new( 0x00, 0x00, 0x7f )
+ );
    $self->StyleSetForeground( 11, Wx::Colour->new( 0x00, 0x00, 0xff )
+ );
    $self->StyleSetForeground( 12, Wx::Colour->new( 0x7f, 0x00, 0x7f )
+ );
    $self->StyleSetForeground( 13, Wx::Colour->new( 0x40, 0x80, 0xff )
+ );
    $self->StyleSetForeground( 17, Wx::Colour->new( 0xff, 0x00, 0x7f )
+ );
    $self->StyleSetForeground( 18, Wx::Colour->new( 0x7f, 0x7f, 0x00 )
+ );
    $self->StyleSetBold( 12, 1 );
    $self->StyleSetSpec( Wx::Scintilla::SCE_H_TAG, "fore:#0000ff" );
    
    foreach my $i (0..18) {
        $self->StyleSetBackground( $i, Wx::wxBLACK() ) ; 
        
    }
    $self->StyleSetForeground( Wx::Scintilla::SCE_PL_IDENTIFIER, Wx::w
+xWHITE() ) ; 
    

    $self->StyleSetBackground( Wx::wxSTC_STYLE_DEFAULT(), Wx::wxBLACK(
+) ) ; 
    #$self->StyleClearAll();
    $self->StyleSetBackground( Wx::wxSTC_STYLE_LINENUMBER(), Wx::wxRED
+());
    $self->StyleSetForeground( Wx::wxSTC_STYLE_DEFAULT(), Wx::wxWHITE(
+));    

   $self->AddText("Hello how are you.");
    $self->StyleSetForeground( Wx::wxSTC_STYLE_DEFAULT(), Wx::wxWHITE(
+));

    $self->SetLexer(Wx::Scintilla::SCLEX_PERL);
    
   #$self->SetLexer(Wx::Scintilla::SCLEX_PHPSCRIPT);

    # $self->SetLexer(Wx::Scintilla::SCLEX_PYTHON);
    
    # $self->SetLexer(Wx::Scintilla::SCLEX_NULL);

    $self->SetLayoutDirection(wxLayout_LeftToRight)
        if $self->can('SetLayoutDirection');
    
    return $self;
}

#####################
package main;

my $app = Demo::Editor->new;
$app->MainLoop;
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