jumpy scroll 4

docs/macos.md

@@ -93,7 +93,7 @@ Closing the window leaves the app running with its store and streams (`applicati
 
 ## Views
 
-- **Transcript and Lead.** `TranscriptBuilder` is a pure function from events to a list of rows: user and agent messages, consecutive tool calls folded into one group with its summary ("Read file ×3"), subagents nested with their status, pending tool calls and running subagents (background ones included after the turn ends) outlined in the accent colour with a 0.6s fade, thinking, the byre prompt collapsed, held turns, `NO_REPLY` turns folded away, handoffs, snapshot rows with changes, fork and review, and notes for the other event kinds. It is incremental: a new batch extends the existing rows. The view is a `ScrollView` with a `LazyVStack`, stuck to the bottom unless the user has scrolled more than 80 points up. While the user is scrolling (`onScrollPhaseChange`), content height changes from rows the `LazyVStack` lays out late only update whether it is stuck and never pull it back to the bottom. Each Markdown text run's `NSTextView` measures its height with one TextKit stack kept in its coordinator, and a repeat measurement at the same width and text returns the stored size. Pending sends show at the end until the server echoes them. A turn summary counts as read when its row is on screen and the app is active (`markSummaryRead`). The head carries Compact (with its context-usage fill), Sync from main, Merge and Discard.
+- **Transcript and Lead.** `TranscriptBuilder` is a pure function from events to a list of rows: user and agent messages, consecutive tool calls folded into one group with its summary ("Read file ×3"), subagents nested with their status, pending tool calls and running subagents (background ones included after the turn ends) outlined in the accent colour with a 0.6s fade, thinking, the byre prompt collapsed, held turns, `NO_REPLY` turns folded away, handoffs, snapshot rows with changes, fork and review, and notes for the other event kinds. It is incremental: a new batch extends the existing rows. The view is a `ScrollView` with a plain `VStack`, stuck to the bottom unless the user has scrolled more than 80 points up. The stack isn't lazy because a `LazyVStack` estimates the height of rows it hasn't shown yet and corrects it when they scroll into view, without moving the scroll offset, so scrolling up through rows not yet shown jumped by each correction; SwiftUI can't move the offset mid-scroll without stopping its momentum. While the user is scrolling (`onScrollPhaseChange`), content height changes only update whether it is stuck and never pull it back to the bottom. The lead pages back when the view comes within one screen of the top: the fetched page is held while the scroll phase is scrolling and inserted once it is idle (`ChatModel.older`, `prependOlder`), and the next geometry change moves the offset down by the height added, so the rows on screen stay put; a page that adds no rows (all folded `NO_REPLY` turns) fetches the next one at once. Each Markdown text run's `NSTextView` measures its height with one TextKit stack kept in its coordinator, and a repeat measurement at the same width and text returns the stored size. Pending sends show at the end until the server echoes them. A turn summary counts as read when its row is on screen and the app is active (`markSummaryRead`). The head carries Compact (with its context-usage fill), Sync from main, Merge and Discard.
 - **Composer.** A `TextEditor`, with paste and drop handled as in "Gaps in SwiftUI". Text, the model menu (filtered to the live session's vendor), Interrupt and Send. Enter sends, Shift-Enter adds a newline, and Enter during IME composition does neither. Pasted or dropped PNG, JPEG, GIF and WebP images become thumbnails with ×, uploaded to `POST /api/blobs` on send; any other image `NSBitmapImageRep` decodes, such as TIFF, is converted to PNG first, its size checked after conversion. A failed send puts the text and images back and shows the error.
 - **Inbox.** The selected task's oldest open item, rendered from its Markdown context with each choice's marker replaced by a clickable block (pick-one, sends at once) or checkbox (pick-any, with Submit), the "recommended" tag, image-choice grids, attachments, Let the agent decide, Other… and, for errors, Reply… and Dismiss. Arrow keys move between choices. A 409 shows its error. The Changes summary line sits above it.
 - **Changes, Files, Reviews, Workflow, Project, Status, Settings.** Including the pinned-snapshot stepper, open-diff memory, per-task place in Files, finding diffs with Fix and Ignore, nested subtasks, TODO Start and Discuss, rate-limit pace bars and lead notes. The Workflow tab draws its stage graph natively from the `WorkflowRun` (stages as boxes coloured by state, `after` as edges, laid out top to bottom by depth) with the layout and drawing code from "Diagrams", fed from the run's data rather than Mermaid text.
@@ -163,7 +163,7 @@ Places where SwiftUI alone may fall short, each checked side by side against its
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 | Enter sends, Shift-Enter newline, nothing during IME composition | `TextEditor` with `onKeyPress` | `NSTextView` in an `NSViewRepresentable`, sending from `doCommand(by: insertNewline:)`, which the input method never reaches while it holds marked text | No fallback: `onKeyPress(.return)` runs before the `TextEditor`'s `NSTextView` and its input context. It sends, and returns `.ignored` for Shift so the text view adds the newline (checked by hand). Because it runs first, it must also return `.ignored` while the focused text view's `hasMarkedText()` is true, or Return sends the draft mid-composition. An in-process test that set marked text with `setMarkedText` and delivered a Return `NSEvent` to the window showed both: an unguarded handler sent the draft with the marked text still pending, and the guarded one sent nothing and passed Return on to the text view. From there the input method handles Return as it does in any `NSTextView`, so the `NSTextView` fallback would behave the same. The guard reads the key window's first responder, which is the composer while the user types |
 | Image paste and drop into the composer | `onPasteCommand` and `onDrop` | The same `NSTextView`, overriding `paste(_:)` and drag handling | No fallback, but not through these two modifiers: `TextEditor`'s own text view takes ⌘V and drops before `onPasteCommand` and `onDrop` and inserts the file's path as text. Instead the app replaces Edit's pasteboard group (`CommandGroup(replacing: .pasteboard)` with Cut, Copy, Paste and Select All sent to the first responder): Paste attaches the clipboard's image when the composer has focus (`focusedValue`) and otherwise sends the ordinary `paste:`, so text paste works in every field and the terminal. Drops land on a `Color.clear` overlay on the `TextEditor` with `onDrop` and `allowsHitTesting(false)`: it still receives the drag, and clicks and typing pass through to the editor (with hit testing on, the editor can't be clicked). Both attach thumbnails and upload to `POST /api/blobs` |
-| Transcript of a long task (thousands of events) scrolling smoothly and staying stuck to the bottom | `LazyVStack` in a `ScrollView` | `List` with its own row reuse | No fallback: on a 5258-event task, `LazyVStack` scrolls smoothly, stays at the bottom while rows arrive and a message streams (`ScrollPosition.scrollTo(edge: .bottom)` on each change while within 80 points of the bottom, tracked with `onScrollGeometryChange`), and stays put when scrolled up. `List` passed too |
+| Transcript of a long task (thousands of events) scrolling smoothly and staying stuck to the bottom | `VStack` in a `ScrollView` | `List` with its own row reuse | No fallback: the stack stays at the bottom while rows arrive and a message streams (`ScrollPosition.scrollTo(edge: .bottom)` on each change while within 80 points of the bottom, tracked with `onScrollGeometryChange`), and stays put when scrolled up. A `LazyVStack` jumped while scrolling up through rows it hadn't shown yet, as it corrected their estimated heights |
 | Selecting text across blocks and messages | `textSelection(.enabled)` selects within one `Text` only | A selectable `NSTextView` in an `NSViewRepresentable` | Fallback used within a message: `MarkdownView` draws each run of consecutive paragraphs, headings and lists (bullets as text, hanging indents from tab stops and paragraph styles) as one `NSAttributedString` in one non-editable `FlowText` text view, so a drag crosses blocks and bullets. Code blocks, diffs, tables, quotes, diagrams, `<details>`, paragraphs with images and choice lists stay SwiftUI views and end a run. Messages are still separate views, so a drag selects within one run of text in one message and each message is copied on its own |
 | The terminal | No terminal view in SwiftUI | SwiftTerm's AppKit `TerminalView` in an `NSViewRepresentable` | Fallback used, as planned: SwiftTerm over `URLSessionWebSocketTask` gives a working shell; Ctrl-C, Ctrl-L, Ctrl-K and Ctrl-R reach it. A local `keyDown` monitor takes Ctrl-K/P/L/S// as Go shortcuts except while the first responder is the `TerminalView` |
 | Font from `mac/fonts/` | Core Text | Convert the files to TTF in the build script if Core Text refuses them | No fallback: Core Text reads the woff2 files and their `wght` axis (200–800) |