Form (Anonymous) Submission Fails in Pages mode with Signature Widget

[eprager412]

Description
Form (Anonymous) Submission Fails for Pages Theme with Signature Widget

To Reproduce
Steps to reproduce the behavior.

1. Open attached form in mode /single/full/participant/
   MUTLIPAGEv10.xform.txt
2. Put something in the signature drawing
3. Go to the next page and add a date value
4. Submit

Expected behavior
The form submits successfully

Actual behavior
The form does not submit, it hangs with a console error.

Screenshots

[MartijnR]

I can reproduce it with:

collect/full/participant: http://localhost:8005/single/full/participant/69da5267c3edeaf9f208c3ab706958fd?ecid=1

regular OC: http://localhost:8005/single/fs/i/x3Rsw83W?ecid=1
regular ODK-style: http://localhost:8005/x3Rsw83W (also broken, but different error)

• check enketo/enketo-express: http://localhost:8005/x3Rsw83W, same problem

However, it does not occur with http://localhost:8005/widgets

It may have something to do with the canvas being hidden. Yes, simplified form: http://localhost:8005/3lxZPDBt3ys6WL7zsZpY5BcPYWHDhGc

• check enketo/enketo-core or enketo-express and file bug report if not already existing => A drawing/annotation/signature that is not on the last page fails to be extracted from the canvas enketo/enketo#22
• review PR https://github.com/enketo/enketo
• update this repo with enketo-core 8.0.0 and check if the 'breaking changes' cause issues for OC (or switch fork to monorepo itemset issue enketo/enketo#150)
  there is an issue with updating to 8.0.0 because at least one css path in Enketo-core is now referring to the monorepo file structure.

[pbowen-oc]

Reopening until this is tested.