Apply additional class(es) to modal dialog's overlay div

When creating a dialog, it is possible to specify custom class(es) to be added to the dialog (to facilitate additional theming):

$( ".selector" ).dialog({ dialogClass: 'alert' });

It would be nice if this class were added to the overlay

div

in addition to the dialog's

div

so that theming can be applied to the dialog's overlay background as well. For example, I might want the overlay to have a different pattern when I'm displaying a critical message versus an informational message.

With this change, I can just add to my CSS:

.ui-widget-overlay.critical-alert { background:red; }

...or whatever to help call attention to the fact this is an important message.

Possible regression: anyone who wasn't careful with their CSS selectors when theming custom-classed dialogs might find their overlay

div

s look strange after upgrading. As an example, if I had:

.critical-alert { border:2px solid red; }

...then both the dialog and [now] the overlay will have a red border. However, if my selector was

.ui-dialog.critical-alert

, then I'd be fine.