core-bundle/src/Resources/contao/dca/tl_user.php
public function checkAdminDisable($varValue, Contao\DataContainer $dc)
	{
		if ($varValue == 1 && $this->User->id == $dc->id)
		{
			$varValue = '';
		}

		return $varValue;
	}
public function checkAdminDisable($varValue, Contao\DataContainer $dc)
	{
		if ($varValue == 1 && $this->User->id == $dc->id)
		{
			$varValue = '';
		}

		return $varValue;
	}
Prevent administrators from disabling their own account

@param mixed                $varValue
@param Contao\DataContainer $dc

@return mixed