Add the tag <can_be_empty>1</can_be_empty> with the field in system.xml file and now you should be enable to Unselect the multi select values.
Ex:
<field id="hideprice" translate="label" type="multiselect" sortOrder="1" showInDefault="1" showInWebsite="1" showInStore="1"> <label>Hide Price For</label> <source_model>PHPCodez\Permission\Model\Config\Source\Group\Multiselect</source_model> <can_be_empty>1</can_be_empty> </field>
<?php
namespace PHPCodez\Disableaddtocart\Helper;
use \Magento\Framework\App\Helper\AbstractHelper;
use \Magento\Framework\App\Config\ScopeConfigInterface;
use \Magento\Store\Model\ScopeInterface;
use \Magento\Customer\Model\Session;
class Data extends AbstractHelper {
protected $_scopeConfig;
protected $_customerSession;
public function __construct(ScopeConfigInterface $_scopeConfig,Session $_customerSession) {
$this->_scopeConfig = $_scopeConfig;
$this->_customerSession = $_customerSession;
}
public function getDisabledGroups($scope = ScopeConfigInterface::SCOPE_TYPE_DEFAULT) {
$disabledGroups = $this->_scopeConfig->getValue('phpcodez/parameters/disableaddtocart',ScopeInterface::SCOPE_STORE);
return $disabledGroups;
}
public function getCustomerGroup(){
return $this->_customerSession->isLoggedIn()?$this->_customerSession->getCustomer()->getGroupId():0;
}
}