[Plugin: Sponsors Slideshow Widget] Transition effects inactive & image superposition

The widget appears in the sidebar with its title, but my test with two sponsor logos had the both of them appear at once, superimposed, with no sliding effect. So I had to deactivate it.

I am using the Specialist theme (https://templatic.com/cms-themes/specialist-business-wordpress-theme) that has it’s own slider on the main page, maybe there’s a conflict there?