Stall Diagnostics

A frozen window is the least informative failure a desktop app can hand you. You do not know whether it crashed, whether the machine is thrashing, or whether one of your own agents did it — so you wait, click a few more times, and eventually force-quit and lose the session. 1DevTool now watches its own main thread and tells you what happened. While the window is unresponsive a red dot sits in the status bar, so you know the app is stalled rather than dead and you stop clicking. When it recovers, a short toast reports the facts: *“1DevTool paused 6.2 s while system CPU was 98% — top: claude, node”*. Every stall is kept for the session and rendered in the same plain wording in the Resource Manager's **Recent stalls** list and under **Settings → General → Diagnostics** — *“Main paused 3.1 s in command `git` while system CPU was 25%”*, or *“Window paused 1.8 s (renderer did not respond)”*, naming the request, background poll or command that was in flight at the time. That settings page also holds the **Main-thread watchdog** toggle, the **Stall threshold**, an opt-in for **Send stall reports**, and the **Lower terminal priority under memory pressure** switch. A freeze becomes something you can report with numbers rather than a feeling.