silverstripe-framework/admin/templates/Includes/ModelAdmin_left.ss

<div id="SearchForm_holder" class="leftbottom ss-tabset">		
	<% if SearchClassSelector = tabs %>
		<ul>
			<% control ModelForms %>
				 <li class="$FirstLast"><a id="tab-ModelAdmin_$Title.HTMLATT" href="#{$Form.Name}_$ClassName">$Title</a></li>
			<% end_control %>
		</ul>
	<% end_if %>
	
	<% if SearchClassSelector = dropdown %>
		<p id="ModelClassSelector">
			Search for:
			<select>
				<% control ModelForms %>
					<option value="{$Form.Name}_$ClassName">$Title</option>
				<% end_control %>
			</select>
		</p>
	<% end_if %>
	
	<% control ModelForms %>
		<div class="tab" id="{$Form.Name}_$ClassName">
			$Content
		</div>
	<% end_control %>
</div>