Opening to the side has perf problems and does not render chats

[dmitrivMS]

Testing #333402

Create session with 3 chats as described in the TPI.
In the session list clicking Alt+Click all 3 chats -> the UI will freeze for some time, then eventually chats will reopen to the side.

I expect it to either work fast or not freeze the UI.
Also, some of the chats appear empty:

If I open chats individually, I see the transcript correctly.

[sandy081]

Dmitriy Vasyura (@dmitrivMS) Could you please reproduce this once more with the log level set to Trace and share the relevant Agents Window / Agent Host logs from that run? If possible, a performance profile covering the Alt+click sequence and UI freeze would also be very helpful. Please include approximately when the three chats were opened so the freeze and empty-transcript behavior can be correlated in the logs.