Datamatrix not working with fields

[Stefano Mortellaro]

• Version: AppImage (Continuous Integration Snapshots) v3.99.0
• System: Ubuntu 16.04.1

In this scenario:

The text fields are correctly rendered with the corresponding record's value but the datamatrix is always the same, with this value: ${2}

[J Evins]

Oops -- I forgot to expand the barcode data. This should be fixed with commit 03a8e29.