tracks/app/views/shared/_add_new_item_form.rhtml

<%
@todo = nil
@initial_context_name = @context.name unless @context.nil?
@initial_context_name ||= @project.default_context.name unless @project.nil? || @project.default_context.nil? 
@initial_context_name ||= current_user.contexts.first.name unless current_user.contexts.first.nil?
@initial_project_name = @project.name unless @project.nil?
-%>
<div id="todo_new_action_container">

  <div id="toggle_action_new" class="hide_form">
    <a title="Hide new action form" accesskey="n" href="#">&laquo; Hide form</a>
    <%  apply_behavior '#toggle_action_new a:click', :prevent_default => true do |page|
      page << "TracksForm.toggle('toggle_action_new', 'todo_new_action', 'todo-form-new-action',
      '&laquo; Hide form', 'Hide next action form',
      'Add a next action &#187;', 'Add a next action');"
    end
    -%>
  </div>

  <div id="todo_new_action" style="display:block">
    <% form_remote_tag(
      :url => todos_path, :method => :post,
      :html=> { :id=>'todo-form-new-action', :name=>'todo', :class => 'inline-form' },
      :before => "$('todo_new_action_submit').startWaiting()",
      :complete => "$('todo_new_action_submit').stopWaiting()",
      :condition => "!$('todo_new_action_submit').isWaiting() && askIfNewContextProvided()") do -%>

      <div id="status"><%= error_messages_for("item", :object_name => 'action') %></div>

      <label for="todo_description">Description</label>
      <%= text_field( "todo", "description", "size" => 30, "tabindex" => 1, "maxlength" => 100, "autocomplete" => "off") %>

      <label for="todo_notes">Notes</label>
      <%= text_area( "todo", "notes", "cols" => 29, "rows" => 6, "tabindex" => 2) %>

      <input id="default_project_name_id" name="default_project_name" type="hidden" value="<%=@initial_project_name-%>" />
      <label for="todo_project_name">Project</label>
      <input id="todo_project_name" name="project_name" autocomplete="off" tabindex="3" size="30" type="text" value="<%= @initial_project_name %>" />
      <div class="page_name_auto_complete" id="project_list" style="display:none"></div>

      <input id="default_context_name_id" name="default_context_name" type="hidden" value="<%=@initial_context_name-%>" />
      <label for="todo_context_name">Context</label>
      <input id="todo_context_name" name="context_name" autocomplete="off" tabindex="4" size="30" type="text" value="<%= @initial_context_name %>" />
      <div class="page_name_auto_complete" id="context_list" style="display:none"></div>

      <label for="tag_list">Tags (separate with commas)</label>
      <%= text_field_tag "tag_list", nil, :size => 30, :tabindex => 5 %>

      <div class="due_input">
        <label for="todo_due">Due</label>
        <%= text_field("todo", "due", "size" => 12, "class" => "Date", "onfocus" => "Calendar.setup", "tabindex" => 6, "autocomplete" => "off") %>
      </div>

      <div class="show_from_input">
        <label for="todo_show_from">Show from</label>
        <%= text_field("todo", "show_from", "size" => 12, "class" => "Date", "onfocus" => "Calendar.setup", "tabindex" => 7, "autocomplete" => "off") %>
      </div>

      <%= source_view_tag( @source_view ) %>

      <div class="submit_box">
        <div class="widgets">
          <button type="submit" class="positive" id="todo_new_action_submit" tabindex="8">
            <%=  image_tag("accept.png", :alt => "") %>Add action
          </button>
        </div>
      </div>
    <% end -%>

    <script type="text/javascript" charset="utf-8">

      var contextNames = <%= context_names_for_autocomplete %>;
      var projectNames = <%= project_names_for_autocomplete %>

      function askIfNewContextProvided() {
        var givenContextName = $('todo_context_name').value;
        if (givenContextName.length == 0) return true; // do nothing and depend on rails validation error
        for (var i = 0; i < contextNames.length; ++i) {
          if (contextNames[i] == givenContextName) return true;
        }
        return confirm('New context "' + givenContextName + '" will be also created. Are you sure?');
      }

      var projectAutoCompleter = new Autocompleter.Local('todo_project_name', 'project_list', projectNames, {choices:100,autoSelect:false});

      function selectDefaultContext() {
        todoContextNameElement = $('todo_context_name');
        defaultContextName = todoContextNameElement.projectDefaultContextsMap[this.value];
        if (defaultContextName && !todoContextNameElement.editedByTracksUser) {
          todoContextNameElement.value = defaultContextName;
        }
      }
      Event.observe($('todo_project_name'), "focus", projectAutoCompleter.activate.bind(projectAutoCompleter));
      Event.observe($('todo_project_name'), "click", projectAutoCompleter.activate.bind(projectAutoCompleter));
      Event.observe($('todo_project_name'), "blur", selectDefaultContext.bind($('todo_project_name')));

      var contextAutoCompleter;
      function initializeNamesForAutoComplete(contextNamesForAutoComplete) {
        if (contextNamesForAutoComplete.length == 0 || contextNamesForAutoComplete[0].length == 0) {
          return;
        }
        contextAutoCompleter = new Autocompleter.Local('todo_context_name', 'context_list', contextNamesForAutoComplete, {choices:100,autoSelect:false});
        Event.observe($('todo_context_name'), "focus", function(){ $('todo_context_name').editedByTracksUser = true; });
        Event.observe($('todo_context_name'), "focus", contextAutoCompleter.activate.bind(contextAutoCompleter));
        Event.observe($('todo_context_name'), "click", contextAutoCompleter.activate.bind(contextAutoCompleter));
      }

      function updateContextNamesForAutoComplete(contextNamesForAutoComplete) {
        if (contextAutoCompleter) { // i.e. if we're already initialized
          contextAutoCompleter.options.array = contextNamesForAutoComplete
        } else {
          initializeNamesForAutoComplete(contextNamesForAutoComplete)
        }
      }
      initializeNamesForAutoComplete(contextNames);
      $('todo_context_name').projectDefaultContextsMap = eval('(' + <%= @default_project_context_name_map %> + ')');
    </script>

    <%= calendar_setup( "todo_due"  ) %>
    <%= calendar_setup( "todo_show_from"  ) %>
  </div>
</div>