Red cross icon in popups

[Alberto]

Hi, is there any way of delete the close red cross icon in a popup window?
And any way of set it as modal so the user must click on a button to close?
Thanks

[Alberto]

THis css seams to work ok

button.ui-button.ui-corner-all.ui-widget.ui-button-icon-only.ui-dialog-titlebar-close {
    visibility: hidden;
}

Any advice?

[Bruce]

what happens if you press Esc on the keyboard?
What if the user navigates away from the popup using the URL?
What if they just close the browser?