Testbench: DijkstraPE-research recording broken

[atilantera]

Context: testbench/OpenDSA/AV/Development/DijkstraPE-research+player.html
How to produce: Click Grade button
What happens: model answer recording stops to an error

Uncaught TypeError: tree.css(...) is undefined
    addTree http://localhost:8000/OpenDSA/lib/jsav-exercise-recorder-bundle.js:432
    createSvg http://localhost:8000/OpenDSA/lib/jsav-exercise-recorder-bundle.js:505
    setInitialDataStructures http://localhost:8000/OpenDSA/lib/jsav-exercise-recorder-bundle.js:1744
    passEvent http://localhost:8000/OpenDSA/lib/jsav-exercise-recorder-bundle.js:1615
    initialize http://localhost:8000/OpenDSA/lib/jsav-exercise-recorder-bundle.js:1561
[jsav-exercise-recorder-bundle.js:432:24](http://localhost:8000/OpenDSA/lib/jsav-exercise-recorder-bundle.js)

Uncaught TypeError: exercise.modelStructures.filter is not a function
    recordModelAnswerStep http://localhost:8000/OpenDSA/lib/jsav-exercise-recorder-bundle.js:1181
    passEvent http://localhost:8000/OpenDSA/lib/jsav-exercise-recorder-bundle.js:1653
    initialize http://localhost:8000/OpenDSA/lib/jsav-exercise-recorder-bundle.js:1561