The advantage of returning $self is that the user of the code is free to decide to use either style, that is: 
    $window->title('foo');
    $window->border(20);

[download]
Or 
    $window->title('foo')->border(20);

[download]
If you don't return $self, you're taking the decision for the user. Which isn't very friendly.

Now, I don't have a problem with 

    $window->title('foo')->border(20);

[download]
If I see this code, and I've no idea what the title and border methods are, my assumption will be that the title of the window is set to foo, and the border will be 20 pixels wide. I don't see the problem either, unless you have windows with labelled titles, so that there's the possibility that $window->title('foo') returns the 'foo' title.

I probably won't do the chaining as you give. I'd probably write it as: 

$window->title('foo')->border(20);
my $button = $window->child->border(20);
my $label_formatting = $button->child->font_style;

[download]

But I will return $self from accessors.

In reply to Re: Mutator chaining considered harmful by Anonymous Monk
in thread Mutator chaining considered harmful by Aristotle

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.