These docs are for an old release.
Info on upgrading to v4
selectHelper
Whether to draw a “placeholder” event while the user is dragging.
Boolean, default: false
This option only applies to the agenda views.
A value of true will draw a “placeholder” event while the user is dragging (similar to what Google Calendar does for its week and day views). A value of false (the default) will draw the standard highlighting over each cell.
Versions 2.0.3 and prior allowed a function argument for generating custom elements. For later versions, use eventRender instead.