Sender Info on customized Emails doesn't use current Email Default Settings

-- HikaShop version -- : 2.6.4
-- Joomla version -- : 3.6.2
-- PHP version -- : 5.6.16

I recently launched a new HikaShop based site after a long development period and ran into problem with an obscure problem/solution.

It was necessary for us to modify four different Email templates to add company logos and custom information displays. What apparently happened is that whenever the custom template was created, the system embedded Sender Information culled from HikaShop's default configuration. Once values were stored in these custom Sender Information fields, they were stored and re-stored even after we transferred the site from the development server to the live machine and updated the HikaShop's Default Email configurations to meet live requirements. We were never aware that those fields had any values at all since we had never deliberately supplied any, and the fields were hidden on the third tab of the Custom Email editing page.

As a result, the live site was sending these four customized emails using the Sender Information lifted from the development site. It took us about a week to track down exactly what was happening.

Under most circumstances, if you leave a configuration field blank, the system will lift default values from HikaShop, but here, if you save the form with these fields being blank, it appears to grab the default values and store them along with the customization. Unless you know to manually erase those field values, it will retain and use the values which were provided originally and will never update them even if you change the default values.

Can this Custom Email form behavior be corrected to utilize HikaShop's default Email values properly, instead of requiring a manual update each time we change the Email Default settings?

Hello!

I try this code, but not update the sender info (email config settings):

		hikashop_secureField($column);
			
			if(in_array($column, array('from_name', 'from_email', 'reply_name', 'reply_email')) && $config->get($column) == $value){
				$value = '';
			}
			else{

				$mail->$column = $safeHtmlFilter->clean(strip_tags($value), 'string');