Date: 2026-03-02
Status: Canonical deliverable (D3)
Purpose: Standardize scroll, resize, overflow, and empty/loading/error behavior across Graphshell surfaces.

Related:

• ../research/2026-03-02_ux_integration_research.md
• ../implementation_strategy/aspect_command/command_surface_interaction_spec.md
• ../implementation_strategy/workbench/workbench_frame_tile_interaction_spec.md
• ../implementation_strategy/viewer/viewer_presentation_and_fallback_spec.md
• ../implementation_strategy/subsystem_focus/focus_and_region_navigation_spec.md

---

This spec applies to the following surface classes:

1. Graph Pane
2. Node Pane
3. Tool Pane
4. Floating Window
5. Popup Menu
6. Toast
7. Dialog

This spec defines behavior contracts only; visual styling remains owned by theme/presentation specs.

---

• Vertical scroll is allowed on content-bearing surfaces by default.
• Graph Pane uses camera pan/zoom semantics instead of document scroll.
• Dialog bodies and floating-window content regions may scroll vertically when content exceeds viewport.

• Horizontal scroll is disabled by default.
• Horizontal scroll is allowed only for content classes that are inherently wide:
  • URL/address fields
  • tabular diagnostic output
  • preformatted/code-like text blocks
• When horizontal overflow is disabled, truncation policy in §5 applies.

---

Use shared max-height computation for floating and overlay surfaces:

• surface_max_height = viewport_height - margin
• Default margin constants:
  • Popup Menu: 16px
  • Command/Context surface shell: 24px
  • Dialog body: 48px
  • Floating utility windows: 24px

Hard rule: no floating/overlay surface may silently clip vertically without either scroll affordance or explicit truncation cue.

---

Surface class	Resizable	Minimum size	Position persistence
Graph Pane	Via tile split/resize handles	200x150	Frame/tile layout authority
Node Pane	Via tile split/resize handles	300x200	Frame/tile layout authority
Tool Pane	Via tile split/resize handles	200x150	Frame/tile layout authority
Floating Window	Yes	200x150 unless surface-specific override	Session runtime memory
Popup Menu	No	Content-fit with max-height policy	None
Toast	No	Content-fit	None
Dialog	Width/height fixed per dialog type (no freeform drag)	Dialog-specific	None

• Tile-hosted panes persist through Frame/Workbench layout state.
• Floating window position persists for the current session runtime only.
• Popup menus, toasts, and dialogs do not persist position.

---

• Single-line labels/titles truncate with trailing ellipsis.
• Truncation priority order:
  1. Keep interaction affordances visible (close/action controls).
  2. Truncate label text.
  3. Preserve icon/state indicators.

• Hover tooltip must expose full value for truncated text.
• For keyboard-only flow, focused truncated controls must expose full content through accessible name/description.

• Any clipped scroll container must show scroll affordance or explicit fade/cut indicator.
• Silent clipping without cue is forbidden.

---

• Empty states must include:
  • clear reason text,
  • current scope/context,
  • optional primary recovery action.

• Loading indicators must be explicit for async operations.
• Surface class guidance:
  • Pane surfaces: inline spinner/skeleton in content region.
  • Dialogs: inline progress indicator near primary action area.
  • Floating windows: inline loading indicator in body.

• Errors must include:
  • concise reason,
  • impact/scope,
  • recovery action (retry/open settings/dismiss/fallback).
• Viewer fallback/degraded states remain governed by viewer fallback spec; this spec requires the error presentation to be explicit and actionable.

---

• Opening a floating surface must not produce ambiguous z-order.
• Closing returns semantic focus through canonical focus return-path rules.

• Dialogs are top-most within app-owned UI layers.
• Popup menus render above their invoking surface, below blocking dialogs.
• Toasts render in non-blocking overlay layer and must not capture semantic focus.

• Motion is optional and must remain non-blocking.
• Reduced-motion preference disables non-essential open/close animation.

---

Surface class	Scroll	Overflow policy	Empty state	Loading state	Error state
Graph Pane	Camera pan/zoom (not document scroll)	Truncate UI labels; never clip controls silently	Explicit no-content graph message + create/open action	Inline lightweight loading cue during async graph operations	Inline graph-scope error + recovery action
Node Pane	Vertical content scroll	Horizontal scroll only for wide content classes; otherwise truncate + tooltip	Explicit node-content unavailable message + open/route action	Inline spinner/skeleton in content region	Inline error card + retry/fallback action
Tool Pane	Vertical scroll by default	Horizontal for diagnostic tables/code-like text; otherwise truncate + tooltip	Explicit empty tool-state message + primary action	Inline loading indicator in pane body	Inline tool error + recovery action
Floating Window	Vertical body scroll	Max-height policy + explicit scroll cue	Explicit empty body message	Inline loading indicator	Inline error block + action
Popup Menu	Vertical scroll when long	Max-height policy; no horizontal overflow without truncation cues	Explicit “no actions available” state	N/A (open should be immediate)	Inline unavailable/blocked reason
Toast	No scroll	Truncate long text with tooltip/accessibility description	N/A	N/A	Use toast variant with explicit action when recoverable
Dialog	Vertical scroll in body region as needed	Max-height policy + body scroll	Explicit no-content message when applicable	Inline progress indicator	Structured error + primary/secondary recovery actions

---

• Canonical D3 artifact exists at design_docs/graphshell_docs/design/surface_behavior_spec.md.
• Covers Graph Pane, Node Pane, Tool Pane, Floating Window, Popup Menu, Toast, Dialog.
• Scroll, max-height, resize/min-size, truncation, empty/loading/error, and floating lifecycle rules are explicit.
• Control-plane and parity docs are linked/updated for D3 tracking.

• Graph empty state: explicit guidance and first-action path in command palette (Create First Node).
• Frame empty state: explicit actionable fallback remains required by workbench interaction contract.
• Pane empty states: covered by §6 empty-state contract and §8 matrix (Node Pane, Tool Pane).
• Search empty state: command/search surfaces must show explicit “no results” rather than blank list.
• History empty state: tool pane must show explicit no-history guidance with next action.
• Diagnostics empty state: tool pane must show explicit no-samples/no-events guidance.

• Palette surfaces must show disabled actions with explicit unmet-precondition reasons.
• Reason format: "[Action] requires [precondition]. [How to satisfy it]."
• Radial surfaces may omit disabled entries when spatial density constraints prevent readable explanations.

• Implementation path: render/command_palette.rs
  • disabled-action reason tooltips for disabled entries,
  • empty-graph discoverability message + Create First Node action.
• Regression checks:
  • disabled_node_delete_exposes_precondition_reason
  • empty_graph_message_present_when_graph_has_no_nodes

Maintenance rule: any change to surface overflow/empty/loading/error semantics must update this spec and UX parity trackers in the same PR.