https://userapps.support.sap.com/sap/support/knowledge/en/3500433
3500433 - UNCAUGHT_EXCEPTION - /UI2/CX_NWBC error when closing NWBC window | SAP Knowledge Base...
When closing a NWBC for HTML window; the following runtime is generated in the backend Runtime Errors UNCAUGHT_EXCEPTION Except. /UI2/CX_NWBC ABAP Program...