DocumentBuilder.insertDocument() create unique text block not editable

Hello,
we use Aspose Word version 24.8 jdk17 to insert a document into another one.
This is our scenario:

Document parent: DEV-107218-CHILD.docx
Document child: DEV-107218-GRANCHILD.docx

Into document parent is present a content control named DEV-107218-GRANCHILD.docx
Into document child is present simple text.

Using DocumentBuilder.insertDocument(), we want insert the content of document child into the content control present into document parent.

The operation goes fine but if we try to edit the text present into the content control, the text is not editable because appear as a unique text block. Only if we go to Develop and switch on the Design Mode the text become editable. When switch off the Design Mode, the text become not editable.

We would like understand why this is the behavior of this feature.
Is there a way to insert the content of document child into content control of document parent immediately editable?

We attach the test code that you can use to replicate the case.
DEV-107218.zip (58.3 KB)

Thanks.
Regards,
Giulio

@giulio.andolfi You should reset isShowingPlaceholderText option of your SDT:

Document doc = new Document("C:\\Temp\\result-child.docx");
StructuredDocumentTag sdt = (StructuredDocumentTag)doc.getChild(NodeType.STRUCTURED_DOCUMENT_TAG, 0, true);
sdt.isShowingPlaceholderText(false);
doc.save("C:\\Temp\\out.docx");