+For cases 3 and 4 C<$attributes{value_key}> defaults to C<id>,
+C<$attributes{title_key}> defaults to C<$attributes{value_key}>
+and C<$attributes{default_key}> defaults to C<selected>.
+
+In addition to pure keys/method you can also provide coderefs as I<value_sub>
+and/or I<title_sub> and/or I<default_sub>. If present, these take precedence over keys or methods,
+and are called with the element as first argument. It must return the value, title or default.
+
+Lastly a joint coderef I<value_title_sub> may be provided, which in turn takes
+precedence over the C<value_sub> and C<title_sub> subs. It will only be called once for each
+element and must return a list of value and title.
+
+If the option C<with_empty> is set then an empty element (value
+C<undef>) will be used as the first element. The title to display for
+this element can be set with the option C<empty_title> and defaults to
+an empty string.
+
+The option C<default> can be either a scalar or an array reference
+containing the values of the options which should be set to be
+selected.
+
+The tag's C<id> defaults to C<name_to_id($name)>.
+
+=item C<yes_no_tag $name, $value, %attributes>
+
+Creates a HTML 'select' tag with the two entries C<yes> and C<no> by
+calling L<select_tag>. C<$value> determines
+which entry is selected. The C<%attributes> are passed through to
+L<select_tag>.
+
+=item C<input_tag $name, $value, %attributes>
+
+Creates a HTML 'input type=text' tag named C<$name> with the value
+C<$value> and with arbitrary HTML attributes from C<%attributes>. The
+tag's C<id> defaults to C<name_to_id($name)>.
+
+=item C<hidden_tag $name, $value, %attributes>
+
+Creates a HTML 'input type=hidden' tag named C<$name> with the value
+C<$value> and with arbitrary HTML attributes from C<%attributes>. The
+tag's C<id> defaults to C<name_to_id($name)>.
+
+=item C<submit_tag $name, $value, %attributes>
+
+Creates a HTML 'input type=submit class=submit' tag named C<$name> with the
+value C<$value> and with arbitrary HTML attributes from C<%attributes>. The
+tag's C<id> defaults to C<name_to_id($name)>.
+
+If C<$attributes{confirm}> is set then a JavaScript popup dialog will
+be added via the C<onclick> handler asking the question given with
+C<$attributes{confirm}>. If request is only submitted if the user
+clicks the dialog's ok/yes button.
+
+=item C<textarea_tag $name, $value, %attributes>
+
+Creates a HTML 'textarea' tag named C<$name> with the content
+C<$value> and with arbitrary HTML attributes from C<%attributes>. The
+tag's C<id> defaults to C<name_to_id($name)>.
+
+=item C<checkbox_tag $name, %attributes>
+
+Creates a HTML 'input type=checkbox' tag named C<$name> with arbitrary
+HTML attributes from C<%attributes>. The tag's C<id> defaults to
+C<name_to_id($name)>. The tag's C<value> defaults to C<1>.
+
+If C<%attributes> contains a key C<label> then a HTML 'label' tag is
+created with said C<label>. No attribute named C<label> is created in
+that case.
+
+If C<%attributes> contains a key C<checkall> then the value is taken as a
+JQuery selector and clicking this checkbox will also toggle all checkboxes
+matching the selector.
+
+=item C<date_tag $name, $value, cal_align =E<gt> $align_code, %attributes>
+
+Creates a date input field, with an attached javascript that will open a
+calendar on click. The javascript ist by default anchoered at the bottom right
+sight. This can be overridden with C<cal_align>, see Calendar documentation for
+the details, usually you'll want a two letter abbreviation of the alignment.
+Right + Bottom becomes C<BL>.
+
+=item C<radio_button_tag $name, %attributes>
+
+Creates a HTML 'input type=radio' tag named C<$name> with arbitrary
+HTML attributes from C<%attributes>. The tag's C<value> defaults to
+C<1>. The tag's C<id> defaults to C<name_to_id($name . "_" . $value)>.
+
+If C<%attributes> contains a key C<label> then a HTML 'label' tag is
+created with said C<label>. No attribute named C<label> is created in
+that case.
+
+=item C<javascript_tag $file1, $file2, $file3...>
+
+Creates a HTML 'E<lt>script type="text/javascript" src="..."E<gt>'
+tag for each file name parameter passed. Each file name will be
+postfixed with '.js' if it isn't already and prefixed with 'js/' if it
+doesn't contain a slash.
+
+=item C<stylesheet_tag $file1, $file2, $file3...>
+
+Creates a HTML 'E<lt>link rel="text/stylesheet" href="..."E<gt>' tag
+for each file name parameter passed. Each file name will be postfixed
+with '.css' if it isn't already and prefixed with 'css/' if it doesn't
+contain a slash.
+
+=item C<date_tag $name, $value, cal_align =E<gt> $align_code, %attributes>
+
+Creates a date input field, with an attached javascript that will open a
+calendar on click. The javascript ist by default anchoered at the bottom right
+sight. This can be overridden with C<cal_align>, see Calendar documentation for
+the details, usually you'll want a two letter abbreviation of the alignment.
+Right + Bottom becomes C<BL>.
+
+=item C<tabbed \@tab, %attributes>
+
+Will create a tabbed area. The tabs should be created with the helper function
+C<tab>. Example:
+
+ [% L.tabbed([
+ L.tab(LxERP.t8('Basic Data'), 'part/_main_tab.html'),
+ L.tab(LxERP.t8('Custom Variables'), 'part/_cvar_tab.html', if => SELF.display_cvar_tab),
+ ]) %]
+
+=item C<areainput_tag $name, $content, %PARAMS>
+
+Creates a generic input tag or textarea tag, depending on content size. The
+amount of desired rows must be either given with the C<rows> parameter or can
+be computed from the value and the C<cols> paramter, Accepted parameters
+include C<min_rows> for rendering a minimum of rows if a textarea is displayed.
+
+You can force input by setting rows to 1, and you can force textarea by setting
+rows to anything >1.
+
+=item C<multiselect2side $id, %params>
+
+Creates a JavaScript snippet calling the jQuery function
+C<multiselect2side> on the select control with the ID C<$id>. The
+select itself is not created. C<%params> can contain the following
+entries:
+
+=over 2
+
+=item C<labelsx>
+
+The label of the list of available options. Defaults to the
+translation of 'Available'.
+
+=item C<labeldx>
+
+The label of the list of selected options. Defaults to the
+translation of 'Selected'.
+
+=back
+
+=item C<sortable_element $selector, %params>
+
+Makes the children of the DOM element C<$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<$::form-gt;header>.
+
+C<%params> can contain the following entries:
+
+=over 2
+
+=item C<url>
+
+The URL to POST an AJAX request to after a dragged element has been
+dropped. The AJAX request's return value is ignored. If given then
+C<$params{with}> must be given as well.
+
+=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.
+
+=back
+
+Example:
+
+ <script type="text/javascript" src="js/jquery-ui.js"></script>
+
+ <table id="thing_list">
+ <thead>
+ <tr><td>This</td><td>That</td></tr>
+ </thead>
+ <tbody>
+ <tr id="thingy_2"><td>stuff</td><td>more stuff</td></tr>
+ <tr id="thingy_15"><td>stuff</td><td>more stuff</td></tr>
+ <tr id="thingy_6"><td>stuff</td><td>more stuff</td></tr>
+ </tbody>
+ <table>
+
+ [% L.sortable_element('#thing_list tbody',
+ url => 'controller.pl?action=SystemThings/reorder',
+ with => 'thingy',
+ as => 'thing_ids',
+ recolor_rows => 1) %]
+
+After dropping e.g. the third element at the top of the list a POST
+request would be made to the C<reorder> action of the C<SystemThings>
+controller with a single parameter called C<thing_ids> -- an array
+containing the values C<[ 6, 2, 15 ]>.
+
+=item C<dump REF>
+
+Dumps the Argument using L<Data::Dumper> into a E<lt>preE<gt> block.
+
+=item C<sortable_table_header $by, %params>
+
+Create a link and image suitable for placement in a table
+header. C<$by> must be an index set up by the controller with
+L<SL::Controller::Helper::make_sorted>.
+
+The optional parameter C<$params{title}> can override the column title
+displayed to the user. Otherwise the column title from the
+controller's sort spec is used.
+
+The other parameters in C<%params> are passed unmodified to the
+underlying call to L<SL::Controller::Base::url_for>.
+
+See the documentation of L<SL::Controller::Helper::Sorted> for an
+overview and further usage instructions.
+
+=item C<paginate_controls>
+
+Create a set of links used to paginate a list view.
+
+See the documentation of L<SL::Controller::Helper::Paginated> for an
+overview and further usage instructions.
+
+=back
+
+=head2 CONVERSION FUNCTIONS
+
+=over 4
+
+=item C<tab, description, target, %PARAMS>
+
+Creates a tab for C<tabbed>. The description will be used as displayed name.
+The target should be a block or template that can be processed. C<tab> supports
+a C<method> parameter, which can override the process method to apply target.
+C<method => 'raw'> will just include the given text as is. I was too lazy to
+implement C<include> properly.
+
+Also an C<if> attribute is supported, so that tabs can be suppressed based on
+some occasion. In this case the supplied block won't even get processed, and
+the resulting tab will get ignored by C<tabbed>:
+
+ L.tab('Awesome tab wih much info', '_much_info.html', if => SELF.wants_all)