Hello, 

Your computed field approach is correct and is generally the recommended way to determine whether an event should receive special styling.

In Odoo 16, Calendar events are rendered through FullCalendar and OWL components, so simply patching methods like getEventOptions() or eventDataTransform() may not always affect the final DOM output. A cleaner approach is to extend the Calendar renderer/component responsible for event rendering and inject a custom class based on your is_crm_hatched field.

If the requirement is only visual differentiation, using Odoo's native color mechanism is often the simplest and most upgrade-friendly solution. However, if you specifically need the o_event_hatched styling, a custom OWL/Calendar renderer extension is the preferred approach rather than relying solely on CSS or unsupported DOM manipulation.

Hope this works for you! If you need any help implementing this or want a more optimized approach, feel free to reach out for further discussion.

Regards,

Zehntech Technologies Inc.

santosh.sekwadia@zehntech.com

I did it! Here is the code.

is_hatched = fields.Boolean(
        string="¿Está rayado?", 
        compute="_compute_is_hatched",
        store=False
    )

    @api.depends('stage_id')
    def _compute_is_hatched(self):
        for lead in self:
            # Si la oportunidad está en la etapa 'Rallada', activamos el patrón nativo
            if lead.stage_id and lead.stage_id.name == 'Rallada':
                lead.is_hatched = True
            else:
                lead.is_hatched = False

<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <record id="view_crm_lead_calendar_hatched_inherit" model="ir.ui.view">
        <field name="name">crm.lead.calendar.hatched.inherit</field>
        <field name="model">crm.lead</field>
        <field name="inherit_id" ref="crm.crm_case_calendar_view_leads"/>
        <field name="arch" type="xml">
            <xpath expr="//calendar" position="inside">
                <field name="is_hatched" invisible="1"/>
            </xpath>
        </field>
    </record>
</odoo>