Apr 23rd — v7.0.0-rc.2
Version 7 will be released soon. Read the v7 docs
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eventBackgroundColor

Sets the background color for all events on the calendar.

String

You can use any of the CSS color formats such #f00, #ff0000, rgb(255,0,0), or red.

This option can be overridden on a per-source basis with the backgroundColor Event Source Object option or on a per-event basis with the backgroundColor Event Object option.