STV_PR_014: Mark the visible graph boundary with a grey line

Problem report: Mark the visible graph boundary with a grey line STV_PR_014

status: fixed tags: usability, viewport basis: owner evidence: docs/problem-tickets/STV_PR_014_node_disappears_behind_invisible_line.rst priority: unassigned verification_state: passed

Reporter/date: Project owner, 2026-10-24. Reported problem: A node appears partially hidden behind an invisible boundary, making it unclear where the graph’s visible region ends. Observed evidence: The annotated screenshot shows the upper part of the project/root node clipped near the area below the view controls and visible node count. A red ellipse and callout identify the boundary. The screenshot shows 17 visible nodes; this is contextual evidence, not an established condition required to trigger the problem. Expected behavior (language-corrected from the slide): Display a thin grey line separating the region in which nodes are visible from the region in which they are not. The line should make the actual clipping boundary apparent to the reader. Reproduction and environment: Exact steps, browser, operating system, product revision and viewport dimensions were not supplied. The supplied screenshot is the original presentation evidence; independent reproduction details and environment are recorded below. Original report and attachments: The intake identifies slide 1 of PR_node_disappears_behind_invisible_line.pptx as the originating source. Only the normalized RST and exported PNG were supplied in this repository; the PNG is sufficient evidence. Language was corrected without changing intent. Owner-provided screenshot and annotation showing the unmarked boundary. Proposed resolution criteria: A thin grey separator marks the boundary identified in the screenshot. Its position matches the actual boundary where graph nodes become clipped, including after viewport resizing and graph pan/zoom operations. The separator does not obscure node content or intercept graph controls. Existing graph navigation, clipping and interaction behavior remain intact; this report requests a visible boundary marker, not removal of clipping. Affected area: Graph viewport rendering and the boundary adjoining the control region. Rendering responsibility: Accessible view and viewport (STV_SWE_RENDER). Confirmed requirement and interface links are recorded in the analysis below. Analysis and fix plan: .stv-viewport establishes clipping with overflow: hidden. Its parent has an outer border, but this inner edge below the controls/status has no marker. Graph movement can therefore hide part of a node behind a boundary with the same background as the controls. Reproduce partial clipping in Firefox over file/HTTP before changing CSS. Add one thin grey top border on the viewport container, outside the transformed scene; keep its content height 975 px under either host box sizing policy. Add no overlay, event handler or clipping-policy change. Model the exact owner-requested outcome, review its design/test coverage, rebuild packaged assets and test clipping, resizing, pan/zoom, keyboard expansion and independent views. Check installed asset delivery. Rebuild the project demo and validate documentation/evidence paths before closing this report. No release or commit is authorized. Requirement/design path: Make the graph clipping bou... (STV_SHR_056) -> Mark the viewport clipping ... (STV_SWR_062) -> Accessible view and viewport (STV_SWE_RENDER), with Visible viewport boundary d... (STV_TC_SY_062) verification. Round 11: PR014 visible viewport boundary records scoped review and PR014 viewport boundary: development verification retains actual attempts. This is a software-local presentation refinement, not a new system boundary. Reproduction: Firefox 158.0.1 on Windows 11 reproduced partial node clipping in both file/HTTP fixtures. The actual overflow edge has no border (0 px, style none); hit tests and screenshots are retained in the development record. Disposition: Fixed and development-verified. The native grey viewport border is implemented and packaged; 10 targeted Firefox variants and all 60 non-browser checks passed. Before-fix failures remain retained. The normal demo is rebuilt; full capacity/release qualification is outside this presentation-only increment. Historical release records and unrelated requirements are unchanged.