Currently, if you Generate Sample Data where a Collection Generation is involved, Studio will display an incorrect amount of items in the Data Set's Collection until its Properties Panel is closed, then re-opened.

Repro Steps:

1) Open the Ombra Sample from the InternalProjects GitHub.
2) In the Data Panel, under the "Screen_ViewModel", change the Generation Parameters of the "Characters" Data Property to generate between 1 and 12 items.
4) Select the Data Set applied to the Page.

5) Run the Generate Sample Data action.
Observe how at the top of the panel, the amount of Items listed, doesn't match the amount of items displayed in the Collection below it.

Expected Results: The Item Count manifest accurately reflects the amount of items in the Collection.

6) Click onto any other Data Structure in the Data Panel.
7) Select the DataSet once again.
Observe how the Item count is now accurate.