jQuery ui modal window causes gray line

I wanted to change the color of the window surrounding the modal alert-popup in jQuery UI. So I changed it; .ui-widget-overlay { background: white But for some weird reason, a gray line with the previously existing color, shows up in the middle of the screen. I haven't been able to select the element with the Chrome debugger, nor have I been able to find it's class in the jQuery-ui css-file. See image.

Anyone开发者_Python百科 know what could be causing this?

Fixed this. For some reason, my jquery-ui.css file had two .ui-widget-overlay classes defined. Added the background-color as in Williams example to the other class and it worked.