[Experimental UI] Requests take 15–50 min + Tasks panel accumulates 100+ stuck "Running" entries that reappear after close

Environment

• Client: Claude Code web version (claude.ai/code)
• UI mode: New experimental interface (switched after it was introduced; have not reverted to old UI)
• Date: April 2026, since experimental UI became available

---

Problem 1 — Requests processing for 15–50 minutes

After switching to the experimental interface, individual requests that I would not consider complex for an AI of this capability began taking 15 to 50 minutes to complete.

These are standard software-engineering tasks: reading files, making targeted edits, running shell commands, committing — not fundamentally different from what the same session was doing before the UI switch.

Expected: similar latency to pre-experimental-UI sessions (seconds to a few minutes for comparable tasks).
Actual: 15–50 min (different, incomprehensible delays and suspensions are noticeable)

I have not been able to rule out whether this is:

• A server-side regression introduced alongside the experimental UI rollout, or
• Something about the experimental UI's request/stream handling that adds overhead.

---

Problem 2 — Tasks panel accumulates 100+ stuck "Running" entries

In the Tasks panel of the experimental UI, background tasks accumulate as "Running" and never clear themselves.

Current state: I have 100+ entries showing as Running.

Behavior observed:

• Closing the browser tab / session does not remove them — they reappear when the session is reopened.
• There is no "clear all" or "cancel all" action visible in the UI.
• It is unclear whether these stuck entries consume server-side resources, affect request prioritization, or contribute to the slow response times described in Problem 1.

Steps to reproduce:

1. Use the experimental Claude Code web UI for a session with background Bash commands (run_in_background: true).
2. Close and reopen the session.
3. Observe Tasks panel — previous "Running" entries are still listed.
4. Repeat across sessions → count grows unboundedly.

---

Questions / requests

1. Are stuck Running tasks consuming server resources or affecting throughput? If yes, this could partially explain the 15–50 min slowdowns.
2. Is there a way to bulk-clear the Tasks panel? If so, it is not discoverable in the current UI.
3. Is the 15–50 min latency a known regression in the experimental UI? If it is a server-side issue unrelated to the UI, knowing that would help narrow down the root cause.
4. Plan: add a "Cancel all / Clear completed" action to the Tasks panel to prevent unbounded accumulation.

---

Additional context

I did not test whether these problems reproduce in the old (non-experimental) UI — I switched to the experimental UI and stayed there.