It is generally difficult in agile teams, specially those geographically distributed, to keep up with the user experience (UX) issues that emerge on each product increment. UX designers need the help of developers to set up user testing environments and to code improvements to the user interface, while developers are too busy with functionality issues. This paper describes a tool called UX-Painter and shows through a case study, how it may help in the above setting to synchronize UX practices and allow for continuous UX improvement during an agile development. UX-Painter allows designers to set up A/B testing environments, exploring interface design alternatives without the need of programming skills, through predefined transformations called client-side web refactorings. Once a design alternative is selected to be implemented in the application's codebase, UX-Painter may also facilitate this step, exporting the applied refactorings to different frontend frameworks. Thus, we foster a method where UX backlog items can be systematically tackled and resolved in an agile setting.