Symptom

Three issues with Server.Pin nodes inside ProjectScreen’s Hardware section, all hitting the user immediately after they added a fresh unconfigured pin via the project dashboard’s + menu:

1. Wrong icon for unconfigured pins. A pin with pinNumber = 0 (the default) showed up as a black HardwareStatusDot with a “0” in the middle. That’s the same visual the editor uses for configured pins — it suggested the pin had been pinned to GPIO 0, which would be wrong (and on a Pi GPIO 0 is reserved). On the ClientScreen swarm tree, the same node correctly rendered as a raspberry-pi icon (the unconfigured affordance).
2. Click swallowed. Clicking the pin row in the dashboard did nothing. The user had no way to open the editor from ProjectScreen; they had to navigate back to ClientScreen, find the pin in the swarm tree, and edit from there.
3. No spacing between hardware rows. Pin and serial-device rows were rendered as edge-to-edge Boxes with no padding, so they visually merged with each other and with the next section header.

Root cause

1. EditPin.kt’s PinRow(id) always rendered HardwareStatusDot, regardless of whether the pin was configured. HardwareStatusDot reads meta.pinNumber and meta.color and renders a coloured sphere with the pin number — there is no “unconfigured” branch in it. The swarm tree dodged the bug because it goes through IconManager.NodeCompoundImage, which short-circuits the dot for unconfigured pins (hardwareId.isEmpty() || pinNumber == 0) and falls through to the painter-level icon (raspberry_pi_brands).
2. HardwareStatusDot declared onClick: ((PinMetaData) -> Unit) = {} — a default no-op lambda — and unconditionally attached Modifier.clickable { onClick(meta) }. Inside ProjectScreen’s Hardware section the outer Box had its own .clickable { openEditor(...) }, but the inner clickable intercepted the gesture first and ran the no-op. The result: a click target that did precisely nothing.
3. ProjectScreen’s Hardware section just forEach‘d each child into a bare Box. DashboardSection’s outer Column has no verticalArrangement, so siblings sit at 0dp from each other. The other sections happened to mask the issue because their child composables (Card-based LogicGateRow, SerialDeviceRow, etc.) carry their own internal padding; PinRow does not.

Fix

• composeApp/.../server/pin/PinView.kt —
  • Changed HardwareStatusDot.onClick from ((PinMetaData) -> Unit) = {} to ((PinMetaData) -> Unit)? = null, and made the clickable modifier conditional via .then(if (onClick != null) Modifier.clickable {...} else Modifier). Read-only callers (PinRow, PinRowView) now don’t swallow the parent’s gesture; the two existing call sites that do want a click (IconManager.NodeCompoundImage, PiHeaderView) already pass non-null lambdas, so they’re unaffected.
• composeApp/.../server/pin/EditPin.kt —
  • PinRow(id) now branches on meta.isConfigured. Unconfigured pins render node.icon() (which goes through IconManager and produces the raspberry-pi affordance) plus the same "GPIO Pin Not Configured" text the row-mode editor shows in NodeSummaryAndEditor. Configured pins keep the HardwareStatusDot + hardwareId/name labels.
• composeApp/.../krillapp/project/ProjectScreen.kt —
  • Hardware section: each row is now wrapped in a Card (Modifier.padding(PADDING_SMALL) inside) and stacked inside a Column(verticalArrangement = Arrangement.spacedBy(SPACING_SMALL)) so adjacent rows are visually distinct and the section bottom doesn’t bleed into the next header.
• composeApp/src/desktopTest/.../screenshot/Fixtures.kt + Scenarios.kt + ScreenshotCatalog.kt — new project__hardware Roborazzi scenario and projectHardwareSwarm() fixture: a project with one unconfigured pin (default PinMetaData()), one configured pin, and a serial device. Captures the rendered editor so any future regression that re-introduces the black-0 dot for unconfigured pins, removes the spacing, or changes the click-to-configure affordance produces a visible PNG diff.
• docs/assets/screenshots/project__hardware.png — recorded screenshot, committed.

Prevention

• Default-no-op onClick lambdas eat parent gestures silently. When a Composable accepts an onClick it doesn’t always need, the default should be null (and the modifier should be conditionally attached) — never {}. A no-op default still attaches clickable, which still consumes the pointer event before anything underneath sees it. The compiler can’t catch this; reviewers can only catch it if they look. Default to null.
• Two visuals for “configured” vs “unconfigured” state must agree across surfaces. IconManager.nodeIcon() knew about pinNumber == 0; HardwareStatusDot did not. Whenever a node has a meaningful “not configured yet” state, the row composable used in list views should defer to IconManager (via node.icon()) for the unconfigured case rather than reimplementing it. The meta.isConfigured extension on PinMetaData is the right predicate to gate on.
• Sections of richly-rendered child composables need explicit spacing. Don’t rely on individual children carrying their own padding — that worked accidentally for LogicGateRow/SerialDeviceRow because they’re Cards, but broke for PinRow which is a plain Row. The dashboard section’s content should set verticalArrangement = Arrangement.spacedBy(...) so spacing is a property of the section, not a coincidence of the child composable’s choice of wrapper.
• A regression-only screenshot beats hand-testing on real hardware. The bug originally required an iOS or Pi build to reproduce — not because the bug was platform-specific, but because that’s where users actually exercised the project dashboard. A desktop Roborazzi scenario with a fixed PinMetaData() (default values, pinNumber = 0) catches it in CI on every push.