WSOD appears in Drupal During making of new variants performing steps.
node edit form->add new variant->variant type ->panel->selection rules->node type->context continue->choose layout 2 column->continue->render->standard->continue after this white display occur,i am stuck here.what is the problem.
There are some PHP settings that can lead to WSOD. These are as follows:


max_execution_time: Apparently, on WAMP, the default is 30 seconds,
but some administrative pages may take longer than that to process
and load.



  Go to XAMPP/php/php.ini and change :


    max_execution_time = 360



PHP Memory Limits: Another common reason for the WSOD is issues with
memory limit.

memory_limit = 128M