silverstripe-cms/templates/Includes/CMSMain_EditForm.ss

<form $FormAttributes data-layout-type="border">

	<div class="cms-content-fields center">
		<% if Message %>
		<p id="{$FormName}_error" class="message $MessageType">$Message</p>
		<% else %>
		<p id="{$FormName}_error" class="message $MessageType" style="display: none"></p>
		<% end_if %>

		<fieldset>
			<% if Legend %><legend>$Legend</legend><% end_if %> 
			<% loop Fields %>
				$FieldHolder
			<% end_loop %>
			<div class="clear"><!-- --></div>
		</fieldset>
	</div>

	<div class="cms-content-actions cms-content-controls south">
		<% if Actions %>
		<div class="Actions">
			<% loop Actions %>
				$Field
			<% end_loop %>
	
			<% include LeftAndMain_ViewModeSelector SelectID="preview-mode-dropdown-in-content" %>
		</div>
		<% end_if %>
	</div>
</form>