The CSS property 'opacity' will make every child transparent also.
You can use instead background-color
and use rgba
for that on the dialog div (.ui-dialog
if I'm not mistaken), for example:
.ui-dialog {
background-color: rgba(255,255,255,0.5);
}
That means a white color (255,255,255) with half opacity (0.5, goes from 0 to 1, 0 meaning invisible, 1 meaning solid).