Hi @neilb,
This issue has been reported by another community user previously, and it was addressed by the Retool team in a recent update. However, if you're still encountering the issue, the Retool team has also provided a workaround you can use in the meantime.
You can find the workaround and additional details in the related community post here:
Retool Error: Can not find frame ID for given subcontainer 'main8'
If you have any further questions or need assistance, feel free to reach out — we're happy to help!