Summary
Customers in an Organization can't add themselves as request participants with restricted Customer Permissions

Steps to Reproduce

1. Go to the project's Customer Permissions and set Who can customers share requests with? to either
   • "Other customers in their organization. This option only allows them to search for customers in their organization."; or
   • "Any customer in the project, by manually entering an email address."
2. Have an organization with Customer A and B in it;
3. Create a ticket with Customer A as reporter, shared with that Org
4. Logged in as Customer B, on the portal, try to share that ticket with yourself (to add as request participant)

Expected Results
User is added as request participant

Actual Results
User cannot be found. Searching for yourself will only work with the "Any customer or organization, by searching this project. This option allows them to search all customers in the current project." option selected on the Customer Permission settings.

Workaround
Change Customer Permission.