+Makes the children of the DOM element C<$selector> (a jQuery selector)
+sortable with the I<jQuery UI Selectable> library. The children can be
+dragged & dropped around. After dropping an element an URL can be
+postet to with the element IDs of the sorted children.
+
+If this is used then the JavaScript file C<js/jquery-ui.js> must be
+included manually as well as it isn't loaded via C<$::form-gt;header>.
+
+C<%params> can contain the following entries:
+
+=over 2
+
+=item C<url>
+
+The URL to POST an AJAX request to after a dragged element has been
+dropped. The AJAX request's return value is ignored by default. If given then
+C<$params{with}> must be given as well.
+
+=item C<ajax_return>
+
+If trueish then the AJAX request's return is accepted.
+
+=item C<with>
+
+A string that is interpreted as the prefix of the children's ID. Upon
+POSTing the result each child whose ID starts with C<$params{with}> is
+considered. The prefix and the following "_" is removed from the
+ID. The remaining parts of the IDs of those children are posted as a
+single array parameter. The array parameter's name is either
+C<$params{as}> or, missing that, C<$params{with}>.
+
+=item C<as>
+
+Sets the POST parameter name for AJAX request after dropping an
+element (see C<$params{with}>).
+
+=item C<handle>
+
+An optional jQuery selector specifying which part of the child element
+is dragable. If the parameter is not given then it defaults to
+C<.dragdrop> matching DOM elements with the class C<dragdrop>. If the
+parameter is set and empty then the whole child element is dragable,
+and clicks through to underlying elements like inputs or links might
+not work.
+
+=item C<dont_recolor>
+
+If trueish then the children will not be recolored. The default is to
+recolor the children by setting the class C<listrow0> on odd and
+C<listrow1> on even entries.