Redmine/app/views/projects/add_issue.rhtml

<h2><%=l(:label_issue_new)%>: <%= @issue.tracker %></h2>

<% labelled_tabular_form_for :issue, @issue, 
                             :url => {:action => 'add_issue'},
                             :html => {:multipart => true, :id => 'issue-form'} do |f| %>
    <%= f.hidden_field :tracker_id %>
    <%= render :partial => 'issues/form', :locals => {:f => f} %>
    <%= submit_tag l(:button_create) %>
    <%= link_to_remote l(:label_preview), 
                       { :url => { :controller => 'issues', :action => 'preview', :id => @issue },
                         :method => 'post',
                         :update => 'preview',
                         :with => "Form.serialize('issue-form')",
                         :complete => "location.href='#preview-top'"
                       }, :accesskey => accesskey(:preview) %>
<% end %>

<a name="preview-top"></a>
<div id="preview" class="wiki"></div>