Cannot add new structure to a site when the site's default language differs from the portal's default language

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 6.2.10 EE GA1, 6.2.X EE, 7.0.0 M3
• Fix Version/s: 6.2.2 CE GA3 , 6.2.X EE, 7.0.0 M2
• Component/s: WCM
• Labels:
  • liferay-fixpack-asset-framework-12-6210
  • liferay-fixpack-document-management-14-6210
  • liferay-fixpack-dynamic-data-lists-13-6210
  • liferay-fixpack-platform-30-6210
  • liferay-fixpack-social-networking-6-6210
  • liferay-fixpack-wcm-core-20-6210
  • liferay-fixpack-web-content-15-6210
• Branch Version/s:
  6.2.x
• Backported to Branch:
  Committed
• Story Points: 4
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/21030

The issue:
Cannot add new structure to a site when the site's default language differs from the portal's default language

Reproduction steps:
1. Unzip a Liferay 6.2 EE SP6
2. Create a new site
3. Change default language for the Site to (for example) German and available languages to German only (Site Settings->Display settings). Thus, the newly created site should only support the language German.
4. Try to add a new structure -> Will fail with message "Please enter a valid name". Also, default language for the structure fields will be set to English, although site has been set to only support German.

Notes:
Reproduced on 6.2.x and on master.