Forms: Fix not saving forms configuration

When working with Forms you may notice such warning message, indicating that data you've provided into form element (like pricing for select values) may be lost during save:

Saving form with multiple elements means passing lots of POST data to HostBill server, which may be filtered out by php.ini max_input_vars directive.

If you see this error make sure to set value of max_input_vars higher in your php.ini file, like: