## whatever @selected is set to at the beginning
## is how your checkboxgroup will appear on loading
## Choose between one of these two lines
#my @selected = @weekday;  		##--> to select all
#my @selected = ($weekday[#a number]);	##--> to select one

foreach my $selected_day (@weekday) {
	my $checkbuttongroup = $rF->CheckbuttonGroup (
					                -list => [ $selected_day ],
					                -orientation => 'vertical',
					                -variable => \@selected,
					                -font => 'bold',
							)->pack(-anchor => 'nw',
								-side => 'top',
								);
}