Silverstripe 3

DataObject ScheduleEvent managed in ModelAdmin.

I have $db = array('AllDay" => "Boolean");

and $defaults = array("AllDay" => '1');

When I click new scheduleevent button I get the form for inputting the objects data. However even though it setting the value of the checkbox to 1 it does not set checked param to "checked" This means that on a new object create form the checkbox does not look like it is checked when it should.

How are defaults populated in a create form for a dataobject?

I know this is an old topic, but was it ever addressed/fixed? I'm still seeing the same thing your OP says...the checkbox is not being checked in the CMS even with a default => 1 being set.

Confusion of purposes I think.
Defaults on a DataObject are enacted when it is written for the first time.
The form will just be an empty form, as there's no data to read from yet, thus no checked property.
You must manually default the CheckboxField to checked.

I could be wrong, I have not checked.
But I do not believe the EditForm consults a DataObject's default config when there's no data supplied to populate the form.