White Screen when go to checkout from popup link

Hi,

I'm not sure what you mean by "hard coded" ? You mean you modified the code ? Note that there is already a setting called "force menu on checkout" in the HikaShop configuration where you can select the menu item to be used for the checkout. So it does the same and doesn't require modifying the code.

Also, if you get a white screen, please turn on the "error reporting" and "debug mode" settings of the Joomla configuration and try again. It should then display an error message which should tell you where is the problem.