A side thought: since there's usually a preview button around when one is submitting a node for the first time, would such a button be desirable when editing a node?
I have wished that it were so, but I have searched for discussions about this, and found much disagreement. As a workaround, you can use your scratchpad to preview anything you care to write.

Update: ... and came across one final question.
In future posts, please consider making this kind of update into a separate reply instead. It will be easier for other monks to follow the conversation. As it is, no one can tell for sure that my second reply was to the pre-update version of your reply, and my third reply was to the post-update version of your reply. It is clear to you and I today, but it will be less clear to future monks searching for enlightenment.

...have the code run, and come up simply as a rectangle that displays all the information (buttons) in one window.
The window manager should do this automatically. After a good night's sleep, I see that I missed something in my last example. Now that we are not displaying all 30 button sets at once, we no longer need the scrolling, and so $pane can be removed, allowing $frame to become a child of $mw. After this change, the application starts up with the correct size. In diff notation: 

-my $pane = $mw->Scrolled(qw/Pane -scrollbars osow/)->pack(
-  -expand => 'yes',
-  -fill   => 'both',
-);
-my $frame = $pane->Frame->pack();
+my $frame = $mw->Frame->pack();

[download]
Does this do what you wanted?

In reply to Tk MainWindow resizing by Util
in thread Some beginning Tk help by dimmesdale

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.