Issue

Constellation applications are not localized if users are using browser Locale or pxRequestor.pxReqLocale. 

Symptoms and Impact

Constellation localization is not triggered if the operator locale is not defined on the Operator ID record, and the user relies exclusively on the browser locale. 

This behavior differs from the traditional UI, where localization can be invoked purely based on the browser locale without requiring an explicit operator locale.  

This discrepancy can lead to confusion, particularly in environments where operator locales are intentionally not set, and localization is expected to follow browser settings. In some cases, developers may observe partial localization when working in a localized version of Dev Studio.  

Steps to Reproduce

1. The locale in operator id is empty. 
2. Change browser language to any language other than English. The application is not translated. 

Root Cause

This is a product feature gap. 

Constellation localization logic does not fall back to the browser locale. It relies exclusively on the locale defined on the Operator ID record. Unlike the traditional UI, there is no mechanism to automatically derive localization from the browser when the operator locale is not configured. 

Solution

This issue will be resolved in an upcoming release and will be fixed in Pega Infinity ‘26.1. 

The locale used by the UI will be determined using the following order of precedence:   

• Operator locale – If an operator-level locale is configured, it will take priority.  

• Browser locale – If no operator locale is set, the system will use the browser’s preferred locale.  

• Application default bundle – If neither is available, the application’s default localization bundle will be used. 

References

Internationalization and localization 

Creating a new operator ID