Technical note:
Normally, when a widget is included in a widget area, the widget code will use a standard WordPress call to generate its HTML output. This results in a standard way to wrap an individual widget. The exact HTML used to wrap a widget can and usually is controlled by the theme (Weaver Xtreme uses <aside> to wrap every widget.). I don’t know how, but your Discounts and Promotions widget must be bypassing this standard method of generating a widget (the rules), and is instead wrapping itself in a <div>. It might be possible to add custom CSS for the class that widget has to make it display properly (like using display=”inline”), but you might want to ask the plugin’s developer how to make it behave properly for a horizontal widget area.