VisualSetings with Empty DataView

[cmholden]

I am developing a custom visual that on some occasions does not need any input data from the Fields and hence the DataView is empty. Using the following in capabilities.json:

"supportsEmptyDataView": true,

This works fine. 

The problems arises with the property settings in the update function. I have a popup dialog that allows a user to set a hidden property and then stores the result in the  visual class with:

this.visualHost.persistProperties(objects);

When I access the properties in update() with; 

this.visualSettings = VisualSettings.parse<VisualSettings>(dataView);

This again works fine if there is data in the DataView. However, with no data, only the default values are returned. I also notice that if I manually set a property as a user, the missing property then becomes available in the update method - so the data are actually there but not processed unless a data field is added or a property updated. 

I imagine that there is a call made somewhere the does this in the background i.e forces the properties to be enumerated. Is it possible to fire this programatically so that I don't have to force the user to add a dummy data field - or is there some other way of making the property available?