Saving State of SubTree Expander

I have noticed then when saving a diagram to JSON the “SubTreeExpander” state is not saved… is it possible to save this state?

Only what you want saved gets saved in the model, so you’ll need to add a two-way data binding. On your group template add:

new go.Binding("isSubGraphExpanded", "expanded").makeTwoWay(),

Perfect !!!

Just what I needed - thank you