chat: avoid session switch height flicker#319227
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roblourens merged 3 commits intoJun 1, 2026
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Only schedule first-measurement chat row height updates when the measured row would otherwise exceed the list's allocated height. This preserves the cutoff fix from PR 318385 without reintroducing first-measurement relayouts for rows that already fit. (Written by Copilot) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Pull request overview
This PR adjusts chat list row height scheduling to avoid unnecessary first-measurement updates that can cause session-switch flicker, while retaining updates when the initial render would clip content.
Changes:
- Adds a helper for deciding whether an initial chat row height change should be scheduled.
- Tracks the list-allocated row height during rendering.
- Adds focused browser unit coverage for the scheduling decision.
Show a summary per file
| File | Description |
|---|---|
src/vs/workbench/contrib/chat/browser/widget/chatListRenderer.ts |
Adds allocated-height tracking and gates first-measurement height updates. |
src/vs/workbench/contrib/chat/test/browser/widget/chatListRenderer.test.ts |
Adds unit tests for the initial height scheduling helper. |
Copilot's findings
- Files reviewed: 2/2 changed files
- Comments generated: 1
Compare initial chat row measurements against the actual allocated height instead of the ceiled allocation so fractional row heights still schedule a corrective update when they would clip content. (Written by Copilot) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Keep the fractional allocated-height coverage on the clipping case: a 121px normalized measurement against a 120.1px allocated row. A 120px normalized measurement already fits 120.1px and should not schedule a corrective height update. (Written by Copilot) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
bhavyaus
previously approved these changes
Jun 1, 2026
justschen
approved these changes
Jun 1, 2026
roblourens
deleted the
agents/pr-318385-added-a-new-flicker-when-switching-cc2eea45
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Summary
Validation
(Written by Copilot)