Changing the search parameters in search preview/seach and select for Contact?

This should be the out-of-the-box functionality. When I'm on a Case and I start typing it uses both the first and last name in the search.

Unless you have made a customization this is how it should function.

If you have a custom default filter it will likely be in custom/Extension/modules/Contacts/Ext/clients/base/filters/default/default.php

or at least in that directory.

The vardefs for the filter will have a quicksearch_field that will look something like:

  'quicksearch_field' => [
      [
          'first_name',
          'last_name',
      ],
      'email',
  ],

which, in this example, tells the system to search for a combination of first and last name or look for matches in an email address.

It could be that someone took out last name from your default search.

FrancescaS

Thanks Jeff. We're working with a Third Party that is helping us set everything up. I was hoping this may be something I could fix myself without asking them to fix it but clearly there's something in their build that has changed the OOTB functions so it doesn't include the last name in the search. Looks like I will have to ask them. Appreciate your confirmation that it should be OOTB and the image. Cheers

Thanks Francesca. Should I be able to see 'custom' in the Administration area? I'm not developer but do have an Admin User so wondering if the custom/Extension/modules/Contacts/Ext/clients/base/filters/default/default.php or directory is visible to me? 
We've been working with Third Party to help us set this up and was hoping I might be able to fix this myself but may require the developer.

The custom directory is something you work with in code.
When you use Studio you are actually modifying files in that directory but I think this particular one needs to be modified in code.

Thanks Francesca.