Deluge insert row does not trigger "On add Row" Workflow

Hello,

i have a Form with a Subform. On Load, i add some Rows to the Subform dynamicaly with:

row = Meetings.People();

row.Selected="Bob";

input.People.insert(row);

there is a Dropdown field in the Subform. On Add Row, i filled this Dropdown with:

row.dropdown.add("Value1");

row.dropdown.add("Value2");

And this worked only if i add a Row manually.

Is it possible to trigger the "On Add Row" Workflow by adding Rows with "insert" in a subform?