=for comment based on iup-3.9 - http://www.tecgraf.puc-rio.br/iup/en/elem/iupscrollbox.html
=head1 NAME
IUP::ScrollBox - [GUI element] container that allows its child to be scrolled
=head1 DESCRIPTION
Creates a native container that allows its child to be scrolled. It
inherits from L<IUP::Canvas|IUP::Canvas>.
=begin HTML
<p>
<img src="http://kmx.github.io/perl-iup/img-3.9/elem/iupscrollbox.png ">
</p>
=end HTML
=head1 USAGE
=head2 CREATION - new() method
#standard way
$mlist = IUP::ScrollBox->new( child=>$child, ANYATTRIBUTE=>'any value' );
#or with just 1 parameter
$mlist = IUP::ScrollBox->new($child);
B<child:> (named parameter) reference to an interface element.
B<Returns:> the identifier of the created element, or C<undef> if an error occurs.
NOTE: You can pass to C<new()> other C<ATTRIBUTE=E<gt>'value'> or C<CALLBACKNAME=E<gt>\&func> pairs relevant
to this element - see L<IUP::Manual::02_Elements|IUP::Manual::02_Elements/"new()">.
=head2 ATTRIBUTES
For more info about concept of attributes (setting/getting values etc.)
see L<IUP::Manual::03_Attributes|IUP::Manual::03_Attributes>. Attributes specific to this element:
Inherits all attributes and callbacks of the L<IUP::Canvas|IUP::Canvas>, but redefines a few attributes.
=over
=item L<BGCOLOR|IUP::Manual::03_Attributes/BGCOLOR>
will use the background color of the native parent by default.
=item B<BORDER>
I<(creation only)> the default value is "NO".
=item L<EXPAND|IUP::Manual::03_Attributes/EXPAND>
I<(non inheritable)> the default value is "YES".
=item L<SCROLLBAR|IUP::Manual::03_Attributes/SCROLLBAR>
I<(creation only)> the default value is "YES".
=item L<CLIENTSIZE|IUP::Manual::03_Attributes/CLIENTSIZE>, L<CLIENTOFFSET|IUP::Manual::03_Attributes/CLIENTOFFSET> also accepted.
=back
=head1 NOTES
The box allows the application to create a virtual space for the dialog
that is actually larger than the visible area. The current size of the
box defines the visible area. The natural size of the child (and its
children) defines the virtual space size. So the L<IUP::ScrollBox|IUP::ScrollBox> does
not depend on its child size or expansion, and its natural size is
always "0x0".
The user can move the box contents by dragging the background. Also the
mouse wheel scrolls the contents vertically.
The box can be created with no elements and be dynamic filled
using L<Append|IUP::Manual::02_Elements/"Append()"> or L<Insert|IUP::Manual::02_Elements/"Insert()">.
=head1 EXAMPLES
Unfortunately there are no sample scripts using this element.
=head1 SEE ALSO
The original doc: L<iupscrollbox.html|http://www.tecgraf.puc-rio.br/iup/en/elem/iupscrollbox.html>
=cut