Steps to reproduce:

1. Create some contents under Ibexa Digital Experience Platform content.
2. Use PHP API to create around 2000 contents under Ibexa Platform content, for example:

           $contentType = $this->contentTypeService->loadContentTypeByIdentifier('folder');
           for ($i = 0; $i < 2000; $i++) {
               $contentCreateStruct = $this->contentService->newContentCreateStruct($contentType, 'eng-GB');
               $contentCreateStruct->setField('name', $i . '_name');
   
               $locationCreateStruct = $this->locationService->newLocationCreateStruct(42); //Location ID of Ibexa Platform content
               $draft = $this->contentService->createContent($contentCreateStruct, array($locationCreateStruct));
               $this->contentService->publishVersion($draft->versionInfo);
           }
   

3. Update admin_group limits:

               content_tree_module:
                   load_more_limit: 10000
                   children_load_max_limit: 20000
   

4. Go to Ibexa Platform content.
5. Expand this subtree and scroll down.

Result:
After a bit of scrolling one is presented with the following CSS problem:

Expected result:
There should be no visible problem when extending Content Tree.