Symptom:
Session bubble not be completely cleared during stress test

Conditions:
1. Press history shortcut on phone A.
2. Press session key 1 on phone A.
3. Dial phone B. Answer the call.
4. On phone B, complete early transfer the call to phone C. Answer the call on phone C.
5. End the call on phone C.
6. Exit the existing call history window on phone A.
Repeat the above steps.