#!/usr/bin/perl -w

use strict;
use Wx;

my $backcolor = Wx::Colour->new('#123582');
my $butbackcol = Wx::Colour->new('#198cff');

## Button margin
my $l=5;

## Centre screen workaround
#my $cw=1366/2;
#my $ch=500/2;

package MyFrame;

use base 'Wx::Frame';
# import the event registration function
use Wx::Event qw(EVT_BUTTON);

sub new {
    
    my $ref = shift;
    my $self = $ref->SUPER::new( undef,              # parent window
                                 -1,                 # ID -1 means any
                                 'Variety Control',  # title
                                 [50, 50],         # default position
                                 [100, 150],         # size
                                 );

    my $panel = Wx::Panel->new( $self,            # parent window
                                -1,               # ID
                                );
    
    $panel->SetBackgroundColour($backcolor);
    
    my $button1 = Wx::Button->new( $panel,        # parent window
                                  -1,             # ID
                                  'Next >>',      # label
                                  [$l, 10],       # position
                                  [-1, -1],       # default size
                                  );

    # register the OnClick method as an handler for the
    # 'button clicked' event. The first argument is a Wx::EvtHandler
    # that receives the event
    #
    
    
    $button1->SetBackgroundColour($butbackcol);
    
    EVT_BUTTON( $self, $button1, \&OnClick1 );
    
    my $button2 = Wx::Button->new( $panel,         # parent window
                                  -1,              # ID
                                  '<<Previous',    # label
                                  [$l, 50],        # position
                                  [-1, -1],        # default size
                                  );
## Here is where I am having problems : 

$button2->SetForegroundColour(Wx::Colour->new(177,77,77));            
+  
   $button2->SetBackgroundColour(Wx::Colour->new(177,77,77));
   #$button2->SetBackgroundColour(Wx::Colour->new('red'));
    
    # register the OnClick method as an handler for the
    # 'button clicked' event. The first argument is a Wx::EvtHandler
    # that receives the event
    EVT_BUTTON( $self, $button2, \&OnClick2 );    
    
    my $button3 = Wx::Button->new( $panel,         # parent window
                                  -1,              # ID
                                  'Trash',         # label
                                  [$l, 90],        # position
                                  [-1, -1],        # default size
                                  );

    # register the OnClick method as an handler for the
    # 'button clicked' event. The first argument is a Wx::EvtHandler
    # that receives the event
    EVT_BUTTON( $self, $button3, \&OnClick3 );    

    return $self;
}

# this method receives as its first parameter the first argument
# passed to the EVT_BUTTON function. The second parameter
# always is a Wx::Event subclass
sub OnClick1 {
    my( $self, $event ) = @_;

    #$self->SetTitle( 'Clicked' );
     system("variety","-n");
}

sub OnClick2 {
    my( $self, $event ) = @_;

    #$self->SetTitle( 'Clicked' );
     system("variety","-p");
}

sub OnClick3 {
    my( $self, $event ) = @_;

    #$self->SetTitle( 'Clicked' );
     system("variety","-t");
}

package MyApp;

use base 'Wx::App';

sub OnInit {
    my $frame = MyFrame->new;
    $frame->Centre("wxBoth");


    $frame->Show( 1 );
}

package main;

my $app = MyApp->new;
$app->MainLoop;
[download]

yaourt wx | grep -i installed
2 extra/wxgtk 3.0.2-2 [installed]
3 extra/wxgtk2.8 2.8.12.1-2 [installed]
11 community/wxsqlite3 3.1.1-1 [installed]
43 aur/perl-alien-wxwidgets 0.65-1 [installed] (43)
45 aur/perl-wx 0.9923-1 [installed] (35)
47 aur/perl-wx-perl-processstream 0.32-1 [installed] (8)
48 aur/perl-wx-scintilla 0.40_02-2 [installed] (5)
86 aur/wxformbuilder-bin 3.1.70-2 [installed] (3)
[download]

I'm unable to test this directly (at work atm). I did note one thing in my quick search of the documentation: the paragraph on SetBackgroundColour warns that the method itself does not produce a visible change, the screen must be refreshed first.

1 Peter 4:10

That is it!

$panel->Layout();
[download]

Fixes the problem. My quest for knowledge continues.............. Cheers.

I'd expect that if it does set the background red, the 3d Button effect ends up covering that red color.

Perhaps try a BitmapButton instead?