Font Size Property Unit Issue in Custom Visual

Hello 

I have an issue with creating a custom visual in which I need to be able to set 2 different font sizes from the property pane. The issue is that the first font size control is a slider which allows values from 8-40 whereas subsequent controls allow 0-100 percent.

I can show this using the basic new visualisation

pbiviz new fontVisual
npm install

Then edit capabilities.json to include a second font size property (in this case "fontSize1")

},
                "fontSize": {
                    "displayName": "Text Size",
                    "type": {
                        "formatting": {
                            "fontSize": true
                        }
                    }
                },
                "fontSize1": {
                    "displayName": "Text Size 1",
                    "type": {
                        "formatting": {
                            "fontSize": true
                        }
                    }
                }

 Update settings.ts to include the new property

     // Text Size
      public fontSize: number = 12;
      public fontSize1: number = 12;

Then build and run

pbiviz start

This is the result

Image may be NSFW.
Clik here to view.2 different font size controls 

Is this the expected behaviour? Or is the second font size meant to be a percentage of the first? If not, Is there any way I can make them the same control?

Thanks