fix(tui): scrollbar visibility, findings scrolling, and report navigation

[0xallam]

Addresses two of the three reports in #1005, both regressions from the Textual interface, plus one enhancement to the report dialog.

1. The chat scrollbar is too narrow to select

The width is not the problem — Textual's was also one cell (scrollbar-size: 1 1) with the same near-invisible resting thumb (#chat_history { scrollbar-color: #1a1a1a } on black).

What the port dropped is the feedback. The stylesheet never overrode scrollbar-color-hover / scrollbar-color-active, so Textual's defaults applied and the thumb brightened as the pointer neared it and while it was dragged. In Go there was no such state: #1a1a1a on black, always. Invisible, and a one-column target.

• One resting color for every panel, visible against the background.
• The bar brightens while dragged.
• The grab area extends one column either side, since a single column is not a reasonable mouse target.

Hover was considered and rejected: it needs WithMouseAllMotion, and a full frame is ~5.7ms in the existing benchmark, so re-rendering on every pointer move risks the lag this interface has already been criticised for.

2. The findings list behaves like pagination

vulnOffset was an index into the findings, so the list advanced a whole entry at a time; with wrapped titles that reads as pages. Even the scrollbar snapped to entry boundaries. Textual mounted each finding into a VerticalScroll with overflow-y: auto — line by line.

The offset is now a row. The wheel, the keys and the scrollbar all move continuously, and the list still reads ● title with wrapped lines under the title.

Sequence numbers were tried and reverted: the interface this replaced never had them, and they crowd a sidebar only a couple of dozen columns wide.

3. Stepping between reports (enhancement)

Reading a set of related findings meant closing the report, moving in the list and opening the next one. The dialog now carries its position and a pair of step buttons:

1/3  Next ›                              Copy   Done
2/3  ‹ Prev  Next ›                      Copy   Done
3/3  ‹ Prev                              Copy   Done

Reachable the three ways the other buttons are: clicked, tabbed to and pressed with Enter, or through ← / → directly. A direction is offered only when there is a report that way, and the ends do not wrap — rolling from the last back to the first hides that you reached the end. A new report opens at its top and does not inherit the previous one's copy state.

Two details behind the implementation:

• Both labels carry their arrow (‹ Prev, Next ›) because the click test matches label text against the rendered row, and a finding whose body contains "Next" could otherwise swallow a click.
• Focus is held by label rather than index: stepping to either end drops a button from the row, and an index would then point at the wrong one. Covered by a test.

This is an enhancement rather than one of the reported bugs. Happy to split it out if you would rather keep the PR to the regressions.

Verification

Rendered and inspected each change: the findings list back to ● title with two-space continuation, a findings scrollbar that can now be seen, and the report row at all three positions plus the single-finding case.

Tests added (11): row-granular scrolling, selection scrolling into view, stepping both directions, clamping at both ends, per-position button availability, click activation, Tab reaching every button, Enter on a focused step button, and the focus fallback when a step button disappears.

gofmt, go vet and the full Go suite pass, including GOOS=windows and GOOS=linux builds.

[greptile-apps]

Greptile Summary

The PR restores row-granular findings scrolling, improves scrollbar visibility and mouse targeting, and adds previous/next navigation to the report dialog.

• Uses one findings-row model for rendering, scrolling, selection, and hit-testing.
• Adds active scrollbar feedback and a wider mouse grab area.
• Adds report navigation buttons, keyboard controls, focus handling, and coverage for the new interactions.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
strix/interface/tui/internal/app/vulnerabilities.go	Introduces a shared row-based findings layout and report-navigation state; the previously reported render/interaction width divergence is resolved.
strix/interface/tui/internal/app/view.go	Renders findings with the shared list width and adds active scrollbar coloring.
strix/interface/tui/internal/app/update.go	Adds row-granular scrollbar handling, expanded scrollbar hit targets, and report navigation input handling.
strix/interface/tui/internal/app/findings_test.go	Adds focused coverage for row scrolling, width consistency, report stepping, button activation, and focus fallback.
strix/interface/tui/internal/app/model.go	Adds report-button focus state and unified resting and active scrollbar colors.
strix/interface/tui/internal/app/model_test.go	Updates copy-button and scrollbar tests for the new focus and color behavior.

_{Reviews (3): Last reviewed commit: "lay the findings list out at one width" | Re-trigger Greptile}

[0xallam]

@greptile

[0xallam]

@greptile