src/Extensions/FontIconExtension.php
public function updateCMSFields(FieldList $fields)
    {
        // Insert Icon Tab:
        
        $fields->insertAfter(
            Tab::create(
                'Icon',
                $this->owner->fieldLabel('Icon')
            ),
            'Main'
        );
        
        // Create Icon Fields:
        
        $fields->addFieldsToTab(
            'Root.Icon',
            [
                FontIconField::create(
                    'FontIcon',
                    $this->owner->fieldLabel('FontIcon')
                ),
                ColorField::create(
                    'FontIconColor',
                    $this->owner->fieldLabel('FontIconColor')
                )
            ]
        );
    }
public function updateCMSFields(FieldList $fields)
    {
        // Insert Icon Tab:
        
        $fields->insertAfter(
            Tab::create(
                'Icon',
                $this->owner->fieldLabel('Icon')
            ),
            'Main'
        );
        
        // Create Icon Fields:
        
        $fields->addFieldsToTab(
            'Root.Icon',
            [
                FontIconField::create(
                    'FontIcon',
                    $this->owner->fieldLabel('FontIcon')
                ),
                ColorField::create(
                    'FontIconColor',
                    $this->owner->fieldLabel('FontIconColor')
                )
            ]
        );
    }
Updates the CMS fields of the extended object.

@param FieldList $fields List of CMS fields from the extended object.

@return void