I have the SpeakUp Petition widget on the homepage of my website, underneath slideshow on the right side bar. When I click "Sign Now", the petition form that pops up gets covered by the slider in the back. I tried changing z-index here (wp-content/plugins/speakup-email-petitions/css/widget.css) but it did not work. How can I fix this? I'm using the slideshow that comes with WordPress after I download the Churchope theme. Slider is in JQuery.