Steps to reproduce:

1. Configure proxy to StartHTTPAgentPollers=0
2. Move host with "HTTP Agent"-type item onto this proxy
3. See item is not receiving new values, try to diagnose

Result:
No errors in proxy log.
Item is in normal (not error) state.
Item accepts "Execute now" with success.
"Test" button on item returns value from proxy without problem.

Expected:
Any hint that HTTP Agent is disabled on selected proxy.
Especially that "Test" button getting data from that proxy with no problem is confusing.