The click-filter-delay Element

[Default: 0]
Since 3.0.9 and 3.5.3

It specifies the time, in milliseconds, to filter out consecutive click events. If two click events (including onOK and onCancel) come too close (within the specified delay), the second one will be removed to avoid the denial-of-service attack. A non-positive value turns off this feature.

Prior to ZK 3.5.3, it is default to 390, which means it filters out the second click event if it happens within 390 milliseconds.