How to avoid adding content controller within a content controller

Question

As a user when he/she tries to add a content control we would like to validate that if a content controller is already there as a parent ?

Our Environment

• Platform [PC desktop, Mac, iOS, Office on the web]: Office on the web and desktop Office
• Host [Excel, Word, PowerPoint, etc.]: Word
• Operating System: Windows 10 Pro
• Browser (if using Office on the web): Chrome Version 101.0.4951.54 (Official Build) (64-bit)/ Edge Version 101.0.1210.39 (Official build) (64-bit) / Microsoft® Word for Microsoft 365 MSO (Version 2204 Build 16.0.15128.20158) 64-bit

Expected behavior

As a user when he/she tries to add a content controller we would like to validate that if a content controller is already there as a parent ?

Current behavior

We are unable to validate whether content control is there as parent or not ?

Context

Our application relies heavily on inserting content into the document and we support both browser and desktop office.

await Word.run(async context => {
        const rngDoc = context.document.getSelection();
        const ooxml = `<pkg:package
                xmlns:pkg='http://schemas.microsoft.com/office/2006/xmlPackage'>
               <pkg:part pkg:name='/_rels/.rels' pkg:contentType='application/vnd.openxmlformats-package.relationships+xml'>
                    <pkg:xmlData>
                        <Relationships
                            xmlns='http://schemas.openxmlformats.org/package/2006/relationships'>
                            <Relationship Id='rId1' Type='http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument' Target='word/document.xml'/>
                        </Relationships>
                    </pkg:xmlData>
                </pkg:part>
                <pkg:part pkg:name='/word/document.xml' pkg:contentType='application/vnd.openxmlformats-officedocument.wordprocessingml.document.main+xml'>
                    <pkg:xmlData>
                        <w:document
                            xmlns:w='http://schemas.openxmlformats.org/wordprocessingml/2006/main' >
                            <w:body>
                                <w:p>
                                    <w:sdt>
                                        <w:sdtPr>
                                            <w:lock w:val="unlocked"/>
                                            <w:alias w:val="${item?.alias}" />
                                            <w:tag w:val="&lt;Tag&gt;&lt;Xpath&gt;${item?.xpath}&lt;/Xpath&gt;&lt;/Tag&gt;" />
                                            <w:showingPlcHdr />
                                            <w:dataBinding w:prefixMappings="xmlns:ns0='abc'" w:xpath="${item?.xpath}" w:storeItemID="{00000000-0000-0000-0000-000000000000}" />
                                            <w:text/>
                                         </w:sdtPr>
                                        <w:sdtContent>
                                            <w:r>
                                                <w:rPr>
                                                    <w:color w:val="808080" w:themeShade="80" />
                                                </w:rPr>
                                                <w:t>${item?.placeHolder}</w:t>
                                            </w:r>
                                        </w:sdtContent>
                                    </w:sdt>
                                </w:p>
                            </w:body>
                        </w:document>
                    </pkg:xmlData>
                </pkg:part>
            </pkg:package>`;
        rngDoc.insertOoxml(ooxml, Word.InsertLocation.after);
        return context.sync();
    });