ContextMenu for default group termplate

I have a definition for default group via archetypeGroupData.
The group is create as expected.
Yet, i cannot attach a context menu to it.
I have tried to set
this.diagram.commandHandler.archetypeGroupData.contextMenu = GO(go.HTMLInfo…
show: this.showContextMenu,

but the showContextMenu() is not fired.
Did i set the contextMenu as expected ?

Your code is just modifying the model data, not the Node in the Diagram.

Define the Diagram.groupTemplate to have a GraphObject.contextMenu.

I guess i confused myself…