UC_SENDTO can be defined just in client 0 or in other clients.
When defined in clients other than client 0, the context menu SendTo doesn't appear.
This is a defect
Workaround: Define everything in client 0
Solution:
Update to a fix version listed below or a newer version if available.
Fix version:
Component(s): Automation Engine
Automation.Engine 24.4.1 - Planned in May 2025
The reference for this is bug is DE168420.