Update renderer class: add select box

docs/30_Page/20_Navigation.md

@@ -72,4 +72,20 @@ $aReplace['{{NAVI_LEFT}}']=''
         'nav', ['class'=>'mt-2'],
         $renderAdminLTE->getSidebarNavigation($aSidebarNav)
     );
-```
+```
\ No newline at end of file
+
+### Navigation hacks
+
+#### Sidebar
+
+To render a horizontal line in the sidebar menu, add a navigation item with label '-'
+
+```php
+$aSidebarNav[]=['href'=>'#', 'label'=>'-'];
+```
+
+In your css file add a rule:
+
+```css
+.nav-item hr{color: #505860; border-top: 1px solid; height: 1px; padding: 0; margin: 0; }
+```