diff --git a/_config.php b/_config.php
index c96a49fb..e10207cd 100644
--- a/_config.php
+++ b/_config.php
@@ -1,5 +1,7 @@
 <?php
 
+use SilverStripe\Admin\CMSMenu;
+
 /**
  * - CMS_DIR: Path relative to webroot, e.g. "cms"
  * - CMS_PATH: Absolute filepath, e.g. "/var/www/my-webroot/cms"
diff --git a/code/BatchActions/CMSBatchActions.php b/code/BatchActions/CMSBatchActions.php
index 5dba652f..6424144e 100644
--- a/code/BatchActions/CMSBatchActions.php
+++ b/code/BatchActions/CMSBatchActions.php
@@ -7,7 +7,8 @@ use SilverStripe\ORM\SS_List;
 use SilverStripe\ORM\ArrayList;
 use SilverStripe\ORM\Versioning\Versioned;
 use SilverStripe\Security\Permission;
-use CMSBatchAction;
+use SilverStripe\Admin\CMSBatchAction;
+
 
 
 /**
diff --git a/code/Controllers/AssetAdmin.php b/code/Controllers/AssetAdmin.php
index dcf11681..08ad66b7 100644
--- a/code/Controllers/AssetAdmin.php
+++ b/code/Controllers/AssetAdmin.php
@@ -9,7 +9,6 @@ use SilverStripe\ORM\DataObject;
 use SilverStripe\ORM\SS_List;
 use SilverStripe\Security\Security;
 use SilverStripe\Security\PermissionProvider;
-use LeftAndMain;
 use Session;
 use Requirements;
 use CMSBatchActionHandler;
@@ -51,6 +50,10 @@ use Injector;
 use Director;
 use ArrayData;
 use CMSBatchAction;
+use SilverStripe\Admin\CMSBatchActionHandler;
+use SilverStripe\Admin\LeftAndMain;
+use SilverStripe\Admin\CMSBatchAction;
+
 
 
 
diff --git a/code/Controllers/CMSMain.php b/code/Controllers/CMSMain.php
index e4eb4992..fbd1d822 100644
--- a/code/Controllers/CMSMain.php
+++ b/code/Controllers/CMSMain.php
@@ -3,6 +3,7 @@
 namespace SilverStripe\CMS\Controllers;
 
 use ResetFormAction;
+use SilverStripe\Admin\CMSPreviewable;
 use SilverStripe\ORM\FieldType\DBHTMLText;
 use SilverStripe\ORM\SS_List;
 use SilverStripe\ORM\Versioning\Versioned;
@@ -16,7 +17,10 @@ use SilverStripe\Security\Security;
 use SilverStripe\Security\SecurityToken;
 use SilverStripe\Security\Permission;
 use SilverStripe\Security\PermissionProvider;
-use LeftAndMain;
+use SilverStripe\Admin\CMSBatchActionHandler;
+use SilverStripe\Admin\AdminRootController;
+use SilverStripe\Admin\AddToCampaignHandler;
+use SilverStripe\Admin\LeftAndMain;
 
 
 use SS_HTTPRequest;
@@ -485,14 +489,14 @@ class CMSMain extends LeftAndMain implements CurrentPageIdentifier, PermissionPr
 		$json = '';
 		$classes = SiteTree::page_type_classes();
 
-		$cacheCanCreate = array();
-		foreach($classes as $class) $cacheCanCreate[$class] = singleton($class)->canCreate();
+	 	$cacheCanCreate = array();
+	 	foreach($classes as $class) $cacheCanCreate[$class] = singleton($class)->canCreate();
 
-		// Generate basic cache key. Too complex to encompass all variations
-		$cache = SS_Cache::factory('CMSMain_SiteTreeHints');
-		$cacheKey = md5(implode('_', array(Member::currentUserID(), implode(',', $cacheCanCreate), implode(',', $classes))));
-		if($this->getRequest()->getVar('flush')) $cache->clean(Zend_Cache::CLEANING_MODE_ALL);
-		$json = $cache->load($cacheKey);
+	 	// Generate basic cache key. Too complex to encompass all variations
+	 	$cache = SS_Cache::factory('CMSMain_SiteTreeHints');
+	 	$cacheKey = md5(implode('_', array(Member::currentUserID(), implode(',', $cacheCanCreate), implode(',', $classes))));
+	 	if($this->getRequest()->getVar('flush')) $cache->clean(Zend_Cache::CLEANING_MODE_ALL);
+	 	$json = $cache->load($cacheKey);
 	 	if(!$json) {
 			$def['Root'] = array();
 			$def['Root']['disallowedChildren'] = array();
@@ -734,7 +738,7 @@ class CMSMain extends LeftAndMain implements CurrentPageIdentifier, PermissionPr
 			$form->setValidationExemptActions(array('restore', 'revert', 'deletefromlive', 'delete', 'unpublish', 'rollback', 'doRollback'));
 
 			// Announce the capability so the frontend can decide whether to allow preview or not.
-			if(in_array('CMSPreviewable', class_implements($record))) {
+			if ($record instanceof CMSPreviewable) {
 				$form->addExtraClass('cms-previewable');
 			}
 
diff --git a/code/Controllers/CMSSiteTreeFilter.php b/code/Controllers/CMSSiteTreeFilter.php
index 90d7f219..38aa3416 100644
--- a/code/Controllers/CMSSiteTreeFilter.php
+++ b/code/Controllers/CMSSiteTreeFilter.php
@@ -7,9 +7,10 @@ use SilverStripe\ORM\DataList;
 use SilverStripe\ORM\SS_List;
 use SilverStripe\ORM\Versioning\Versioned;
 use Object;
-use LeftAndMain_SearchFilter;
 use ClassInfo;
 use DateField;
+use SilverStripe\Admin\LeftAndMain_SearchFilter;
+
 
 /**
  * Base class for filtering the subtree for certain node statuses.
diff --git a/code/Controllers/SilverStripeNavigator.php b/code/Controllers/SilverStripeNavigator.php
index 4dcdae6f..50e0d66f 100644
--- a/code/Controllers/SilverStripeNavigator.php
+++ b/code/Controllers/SilverStripeNavigator.php
@@ -9,10 +9,11 @@ use SilverStripe\ORM\Versioning\Versioned;
 use SilverStripe\ORM\FieldType\DBField;
 use SilverStripe\Security\Member;
 use ViewableData;
-use CMSPreviewable;
 use ClassInfo;
-use LeftAndMain;
 use Controller;
+use SilverStripe\Admin\CMSPreviewable;
+use SilverStripe\Admin\LeftAndMain;
+
 
 use SiteTreeFutureState;
 use SilverStripe\CMS\Model\RedirectorPage;
@@ -222,7 +223,7 @@ abstract class SilverStripeNavigatorItem extends ViewableData {
 				(!$currentDraft || ($currentDraft && $this->record->Version != $currentDraft->Version))
 				&& (!$currentLive || ($currentLive && $this->record->Version != $currentLive->Version))
 			);
-		}
+}
 
 		return $this->record->_cached_isArchived;
 	}
diff --git a/code/Model/SiteTree.php b/code/Model/SiteTree.php
index 05c711a4..edc41e9a 100755
--- a/code/Model/SiteTree.php
+++ b/code/Model/SiteTree.php
@@ -19,7 +19,6 @@ use SilverStripe\Security\Permission;
 use SilverStripe\Security\Group;
 use SilverStripe\Security\PermissionProvider;
 use i18nEntityProvider;
-use CMSPreviewable;
 use Director;
 use SilverStripe\CMS\Controllers\RootURLController;
 use ClassInfo;
@@ -52,9 +51,11 @@ use TreeDropdownField;
 use FieldGroup;
 use CheckboxField;
 use ListboxField;
-use AddToCampaignHandler_FormAction;
 use FormAction;
 use i18n;
+use SilverStripe\Admin\AddToCampaignHandler_FormAction;
+use SilverStripe\Admin\CMSPreviewable;
+
 
 /**
  * Basic data-object representing all pages within the site tree. All page types that live within the hierarchy should
@@ -352,13 +353,13 @@ class SiteTree extends DataObject implements PermissionProvider,i18nEntityProvid
 				foreach($alternatives as $alternative) {
 					if($alternative) {
 						$sitetree = $alternative;
-					}
+			}
 				}
 			}
 
 			if(!$sitetree) {
 				return null;
-			}
+		}
 		}
 
 		// Check if we have any more URL parts to parse.
@@ -437,8 +438,8 @@ class SiteTree extends DataObject implements PermissionProvider,i18nEntityProvid
 	/**
 	 * Replace a "[sitetree_link id=n]" shortcode with a link to the page with the corresponding ID.
 	 *
-	 * @param array $arguments
-	 * @param string $content
+	 * @param array      $arguments
+	 * @param string     $content
 	 * @param ShortcodeParser $parser
 	 * @return string
 	 */
@@ -609,7 +610,7 @@ class SiteTree extends DataObject implements PermissionProvider,i18nEntityProvid
 		$currentPage = Director::get_current_page();
 		if ($currentPage instanceof ContentController) {
 			$currentPage = $currentPage->data();
-		}
+	}
 		if($currentPage instanceof SiteTree) {
 			return $currentPage === $this || $currentPage->ID === $this->ID;
 		}
@@ -1467,7 +1468,6 @@ class SiteTree extends DataObject implements PermissionProvider,i18nEntityProvid
 		}
 
 		if(Permission::check('CMS_ACCESS_CMSMain')
-			&& in_array('CMSPreviewable', class_implements($this))
 			&& !$this instanceof ErrorPage
 			&& $this->ID > 0
 		) {
@@ -1552,7 +1552,7 @@ class SiteTree extends DataObject implements PermissionProvider,i18nEntityProvid
 				DB::alteration_message('Contact Us page created', 'created');
 			}
 		}
-		}
+	}
 
 	protected function onBeforeWrite() {
 		parent::onBeforeWrite();
@@ -1877,10 +1877,10 @@ class SiteTree extends DataObject implements PermissionProvider,i18nEntityProvid
 					if($parentPage && $parentPage->exists()) {
 						$link = Convert::raw2att($parentPage->CMSEditLink());
 						$title = Convert::raw2xml($parentPage->Title);
-					} else {
+						} else {
 						$link = CMSPageEditController::singleton()->Link('show');
 						$title = _t('SiteTree.TOPLEVEL', 'Site Content (Top Level)');
-					}
+						}
 					$parentPageLinks[] = "<a class=\"cmsEditlink\" href=\"{$link}\">{$title}</a>";
 				}
 
diff --git a/tests/controller/CMSMainTest.php b/tests/controller/CMSMainTest.php
index ab00bafd..ccd6ef1a 100644
--- a/tests/controller/CMSMainTest.php
+++ b/tests/controller/CMSMainTest.php
@@ -6,6 +6,8 @@ use SilverStripe\ORM\Versioning\Versioned;
 use SilverStripe\ORM\HiddenClass;
 use SilverStripe\CMS\Controllers\CMSMain;
 use SilverStripe\CMS\Model\SiteTree;
+use SilverStripe\Admin\CMSBatchActionHandler;
+
 
 
 /**