Hello Paul,

Thank you for posting in our community.

Valid data mode for numeric editor`s dataMode options is double (what is set in the fiddle provided is decimal). Change this option in the Updating column settings and everything works as expected. For example:

 {
        name: "Updating",
        editMode: "dialog",
        enableAddRow: true,
        columnSettings: [
         {
               columnKey: "ImageUrl",
               readOnly: false
        },
        {
              columnIndex: -1,
              columnKey: 'InStock',
              editorType: 'numeric',
              defaultValue: 0,
              required: true,
              editorOptions: {
              dataMode: 'double',
              textAlign: 'right',
              validatorOptions: {
                    required: {
                        errorMessage: 'This field is required.'
                    },
                    onblur: true
              },
             minDecimals: 10,
             maxDecimals: 10,
             maxValue: 99999999
           },
        validation: true
       }
    ]
 }

A list with all valid values for dataMode option could be found in our API documentation:

http://www.igniteui.com/help/api/2016.2/ui.ignumericeditor#options:dataMode

Your modified fiddle is available at the following link:

http://jsfiddle.net/uofcft8z/7/

Please let me know if you need any further assistance with this matter.