fix(GenericMenu): restore scroll on dropdown-menu panels

[claude]

Why?

Long dropdown-menu-type GenericMenu panels stopped scrolling — e.g. the org switcher's organization list: the panel clips overflowing content instead of scrolling, so items past the visible area are inaccessible.

Before: panel has overflow: hidden with no effective scroll override → items past the available height are cut off and unreachable.
After: the panel scrolls (overflow-y: auto) once content exceeds --radix-dropdown-menu-content-available-height, same as before the regression.

Root cause: Dropdown.module.css's .dropdown-menu-content already declares overflow-y: auto specifically to override the base panel's overflow: hidden (.generic-menu-panel in src/components/GenericMenu/GenericMenu.module.css, line 5). Both rules have equal specificity (single class selectors), and everything is wrapped in one @layer clickui (see plugins/css-colocate/postcss-clickui-layers.ts), so within that layer the rule registered last wins.

The css-colocate build's insertAtTop helper (plugins/css-colocate/import-inject.ts) unconditionally injects each file's own colocated CSS import at the very top of its own compiled JS module — before that module's other imports, including the one that pulls in GenericMenuPanel from GenericMenu. That means Dropdown.css ends up registered before GenericMenu.css in the build output, inverting the intended override order: the base's overflow: hidden (declared later) beats Dropdown's overflow-y: auto (declared earlier), so the panel never scrolls.

Confirmed by building the package and inspecting dist/esm/components/Dropdown/index.js — import "./Dropdown.css"; is literally the first line, ahead of the import that pulls in GenericMenu.

This is a regression introduced by #1097 (styled-components → CSS Modules migration for the GenericMenu cluster): previously, DropdownMenuContent = styled(GenericMenuPanel) guaranteed the override styles were registered after the base by JS module evaluation order; CSS Modules colocation doesn't carry that same guarantee.

How?

• src/components/GenericMenu/GenericMenu.module.css: added overflow-y: auto; to .generic-menu-panel_type_dropdown-menu — the same stylesheet, after the base .generic-menu-panel rule, so the override can never lose to cross-file injection order. This also covers any consumer that renders GenericMenuPanel type="dropdown-menu" directly, without going through Dropdown.Content.
• Left Dropdown.module.css's existing .dropdown-menu-content { overflow-y: auto; } in place (now redundant but harmless) to keep the diff minimal.
• Added a changeset (patch).

Tickets?

• N/A (reported via Slack in #click-ui)

Contribution checklist?

• You've done enough research before writing
• You have reviewed the PR
• The commit messages are detailed
• The build command runs locally (vite build succeeds; verified the fix in the built dist/esm output)
• Assets or static content are linked and stored in the project
• For documentation, guides or references, you've tested the commands

Security checklist?

• All user inputs are validated and sanitized
• No usage of dangerouslySetInnerHTML
• Sensitive data has been identified and is being protected properly
• Build output contains no secrets or API keys

Notes for reviewers

• yarn typecheck and yarn lint:css pass; yarn vitest run src/components/GenericMenu src/components/Dropdown passes (16/16).
• This environment couldn't run the Docker-based Playwright visual-regression suite (tests/overlays/genericmenu.spec.ts). The existing Dropdown/GenericMenu stories used by that suite only render a handful of items that fit within the available height, so overflow-y: auto vs overflow: hidden shouldn't produce any visible pixel diff there (no scrollbar renders unless content actually overflows) — but a reviewer/CI should still confirm the snapshots are unaffected.
• Opened as draft pending a repo maintainer's confirmation that this is indeed how the org switcher renders its panel (it lives in the ClickHouse console app, which wasn't accessible from this session) — the fix is written to be correct for GenericMenuPanel type="dropdown-menu" regardless of which wrapper the consumer uses.

Co-Authored-By: Claude Sonnet 5 noreply@anthropic.com

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Generated by Claude Code

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🦋 Changeset detected

Latest commit: 6f99b3d

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

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@clickhouse/click-ui	Patch

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[DreaminDani]

nice find

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