These docs are for an old release. Info on upgrading to v5
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longPressDelay

For touch devices, the amount of time the user must hold down before an event becomes draggable or a date becomes selectable.

Integer, default: 1000 (1 second)

This value is specified in milliseconds.

Only applicable when the calendar is being used on a touch device. Otherwise, there is no delay.

This setting controls event dragging and date selecting. For further granularity, please see the following settings: