One of the questions, we get fomr customers is how can we re-host the designer in a Read-Only mode. Well, here you go:
For Re-hosting a Flowchart, we have:
this.wd = new WorkflowDesigner();
Going further, to make this Flowchart ReadOnly, add:
ReadOnlyState state = this.wd.Context.Items.GetValue<ReadOnlyState>();
state.IsReadOnly = true;
This should get the designer in the read-only mode so that no other activities can be added or none of the activity properties changed.