Bryan Sharpe
--- a/src/ConfigSplitManager.php
+++ b/src/ConfigSplitManager.php
      }
    }

+    // Process theme dependencies.
+    // @todo module and theme run the same process, should follow DRY.
+    $themes = array_keys($config->get('theme'));
+    $changes = $this->manager->getConfigEntitiesToChangeOnDependencyRemoval('theme', $themes, FALSE);
+
+    $this->processEntitiesToChangeOnDependencyRemoval($changes, $source, $transforming, $splitStorage);
+
+    $completelySplit = array_map(function (ConfigEntityInterface $entity) {
+      return $entity->getConfigDependencyName();
+    }, $changes['delete']);