Property:

org.zkoss.zul.include.mode

Default: auto (5.0)
Default: defer (3.x)
[Since 3.6.2]

It specifies the default mode of the include component. In ZK 3 and prior, the default mode is defer, which is backward-compatible with the prior version. Since ZK 5, the default mode is auto for easier control.

For more information, please refer to ZK Component Reference.