The disable-behind-modal Element

[Default: false]

It specifies whether to disable all elements behind the modal window at the browser. If disabled, the performance is better.

Tip: This option can be considered as obsolete since 3.0.4. The user is almost impossible to change focus to an element behind the modal window, without disabling them.

Note: in ZK 3.0.3 and earlier, the option is default to true.