Message: Undefined property: stdClass

Question

Part of my Dashee widget isn't working.

I'm setting the settings like so...

        $this->settings = array(
            'title' => 'Recent Orders',
            'channel_id' => '6',
            'limit' => '10',
            'field_firstname' => 'orders_firstname',
            'field_surname' => 'orders_surname',
            'field_total' => 'orders_total',
            'custom_url' => '10',
            'status' => 'Processing'
            );

and the title setting works:

<input type="text" name="title" value="'.$settings->title.'" />

And so does channel_id, limit & status. But my custom_url, field_firstname, field_surname, field_total don't:

<input type="text" name="custom_url" value="'.$settings->custom_url.'" />

It just throws this error:

A PHP Error was encountered Severity: Notice

Message: Undefined property: stdClass::$custom_url

What am I doing wrong?