When dialog is disabled, entire region becomes transparent.
All buttons are still works.
I was experimented with this issue, i think, wDialogMsgTemplates.JQDialogOptions.Disable should apply css "ui-state-disabled" on child divs.
Then, all controls inside dialog will become transparent (opacity = 0.35), but dialog div will be filled.
One more thing - when dialog is disabled, all controls should not work (pointer-events: none !important).