We have enhanced our Admin > Dashboard Management component to allow you to disable the automatic preview function, which is the behavior where the Layout tab always displays all the data in the widgets.

Sometimes it is preferable and more efficient to render the results of the widget on demand, rather than all of the time.  By unchecking the Auto Preview configuration, all widgets will display only some basic configuration information for that widget.

If you want to preview the widget, simply right-click and refresh data and the widget will render the data for your review.