H Dan,
On the first issue - The widget is designed with the restriction so there is nothing much you can do to get the widget to display the text in a single line without distorting the checkbox.
The second issue - It should be a case of the widget not refreshing to reflect the change made. I checked the widget for this issue and found that it takes time to refresh, the simplest way to get it to refresh properly is to type in the variable field, click outside so that it looses focus and then click the field again (Clicking any other text field also seems to work fine). This refreshed and updated the field as needed.
Hope this helps.
Marcellus