Redmine/app/views/settings/_display.rhtml

<% form_tag({:action => 'edit', :tab => 'display'}) do %>

<div class="box tabular settings">
<p><label><%= l(:label_theme) %></label>
<%= select_tag 'settings[ui_theme]', options_for_select( ([[l(:label_default), '']] + Redmine::Themes.themes.collect {|t| [t.name, t.id]}), Setting.ui_theme) %></p>

<p><label><%= l(:setting_default_language) %></label>
<%= select_tag 'settings[default_language]', options_for_select( lang_options_for_select(false), Setting.default_language) %></p>

<p><label><%= l(:setting_date_format) %></label>
<%= select_tag 'settings[date_format]', options_for_select( [[l(:label_language_based), '']] + Setting::DATE_FORMATS.collect {|f| [Date.today.strftime(f), f]}, Setting.date_format) %></p>

<p><label><%= l(:setting_time_format) %></label>
<%= select_tag 'settings[time_format]', options_for_select( [[l(:label_language_based), '']] + Setting::TIME_FORMATS.collect {|f| [Time.now.strftime(f), f]}, Setting.time_format) %></p>

<p><label><%= l(:setting_user_format) %></label>
<%= select_tag 'settings[user_format]', options_for_select( @options[:user_format], Setting.user_format.to_s ) %></p>

<p><label><%= l(:setting_gravatar_enabled) %></label>
<%= hidden_field_tag 'settings[gravatar_enabled]', 0 %>
<%= check_box_tag 'settings[gravatar_enabled]', 1, Setting.gravatar_enabled? %>
</p>
</div>

<%= submit_tag l(:button_save) %>
<% end %>