fix(chat): closing the chat tab closes it, instead of reopening on the right

[ndemianc]

Regression from #76, reported from a real build.

A move and a close both end in panel.dispose(), and onDidDispose treated them identically — revealing the sidebar every time. That was correct while the sidebar was home: surrendering the tab meant going home.

With chat.startLocation defaulting to editor it inverts into a trap. Closing the tab pops the panel open on the right, and there is no way to put the chat away at all — close the tab and the panel appears, close the panel and it returns with the next window.

The else branch was the sharp end. With no resolved sidebar view — the normal case now, since the chat opens centred and nobody opens the secondary sidebar — it called focusChatView() unconditionally, which is exactly what revealed the panel.

Dispose can't see the difference on its own, so moveChatToSidebar announces itself with a flag that dispose reads once and clears. A plain close now closes.

What still happens on a close

If a sidebar view is already resolved, it still becomes live — otherwise the conversation would be live nowhere while a resolved view sat there showing a stale hand-over card. Only the reveal is conditional; making a hidden view live costs nothing and is correct the moment the user opens it.

Two existing tests asserted the old behaviour

Updated deliberately, not mechanically:

• "a sidebar that was never resolved is revealed rather than assumed" asserted the reveal on every close. That was the bug, written down as a requirement. It now covers the move.
• The activeWebview invariant pinned an exact list of assignments, so adding a second reset read as a regression. It now states what it means: exactly one place points it at a live surface, and at least one releases it.

Guards

Each bypass-verified by reverting the fix:

bypass	caught
resolved view force-opened on a plain close	✓
the no-view reveal escaping the moving branch — the reported bug	✓
the flag never cleared, so the next close reveals too	✓
dispose unable to see a move at all	✓
the flag set after dispose, so the move reads it stale	✓
the resolved view never becoming live — chat live nowhere	✓

The two other things reported alongside it

The untitled tab at startup is not ours. LevelCode has no workbench.startupEditor override anywhere in its source — that's the editor default or a user setting (workbench.startupEditor: "none" turns it off).

The ResizeObserver loop spam is INFO-level noise from VS Code's own webview harness — we register no ResizeObserver anywhere. I had a plausible mechanism (the empty state's ASCII logo sizes itself from container width with clamp(5px, 3.6cqi, 13px) inside a scrollable container, which can oscillate with the scrollbar) and could not reproduce it: a harness running the real stylesheet at 280/320/340/360px, with the clamp genuinely in its variable range, reported 1 resize callback and 0 loop errors at every width.

Fixing this bug removes the reported scenario anyway, since the sidebar view is no longer force-opened. I'm not shipping a speculative CSS change for something I haven't reproduced — if the spam survives this fix, it's worth its own investigation with that mechanism as the first suspect.

25 tests in chatSurface, 34 suites green.

[Copilot]

Pull request overview

Fixes a regression introduced when the chat’s default start location moved to the editor: closing the chat editor tab was treated like a “move back to sidebar” and would forcibly reveal the secondary sidebar, making the chat effectively impossible to dismiss.

Changes:

• Differentiate “move to sidebar” vs “close tab” by introducing a one-shot movingChatToSidebar flag that onDidDispose reads and clears.
• Make sidebar reveal conditional on an intentional move, while still handing conversation state back to an already-resolved sidebar surface.
• Update chatSurface tests to reflect the new close vs move semantics and tighten the activeWebview invariant.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
extensions/levelcode-ai/extension.js	Adds close-vs-move detection and conditions sidebar reveal behavior accordingly.
extensions/levelcode-ai/test/chatSurface.test.js	Updates and extends tests to pin the regression and the new intended behavior.

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[ndemianc]

Superseded by the editor-only chat: with the sidebar view removed entirely there is nothing to move to, so the close-versus-move distinction this added no longer exists.