PSEDiscreet viewer can not work with a Group of TS (no measures)

Export from a project a DataTypeGroup of TS (do not take also the DataTypeGroup of Measures) and import it someplace else.
Or in a local env, just remove the DataTypeGroup of Measures.
Launch PSE Discreet.
An error will appear in the JS console, and clocking on circles is not possible.
The circles should remain black and of the same size, but the overlay should be displayed, so that the user can visualize a particular TS.