ContentSection import requires that Resource is imported first.

ccm-cms/src/main/java/org/librecms/contentsection/ContentSectionImExporter.java

@@ -18,6 +18,7 @@
  */
 package org.librecms.contentsection;
 
+import org.libreccm.core.Resource;
 import org.libreccm.imexport.AbstractEntityImExporter;
 import org.libreccm.imexport.Exportable;
 import org.libreccm.imexport.Processes;
@@ -49,7 +50,9 @@ public class ContentSectionImExporter
 
     @Override
     protected Set<Class<? extends Exportable>> getRequiredEntities() {
-        return Collections.emptySet();
+        return Set.of(
+            Resource.class
+        );
     }
 
     @Override