Title of sidebar widget does not show

I am using the Contesthopper plugin with the Storefront theme by Woothemes. The Title text of the Contesthopper widget is not showing. It happens regardless of the size of the widget (whether full size or shrunk). However, the title shows when I switch to a different theme. So it is some kind of conflict between the Contesthopper plugin and the Storefront theme.

Suggestions on how to resolve this conflict?