fix(select,filter-dropdown): keep Clear all's menu open and a searching Select's side

[tmccoy14]

What

Two regressions from 4.3.0 that showed up while adopting it in Guardian Studio:

• FilterDropdown's "Clear all" closes the menu. It used to leave it open.
• A searchable Select switches sides during a search. In Studio's Apply Policy dialog, the project select opens above its trigger. Type a query that matches nothing, clear it, and the list is now below the trigger, squeezed into the space left there.

Why

Clear all. In 4.3.0 "Clear all" became a DropdownMenuItem, so keyboard users can reach it. Radix closes a menu whenever an item's onSelect doesn't call preventDefault. The item also unmounts once nothing is selected. When the focused element disappears, focus falls back to an enclosing Dialog, and the browser draws its focus ring around the whole dialog.

Select side. Radix positions the popper with flip() and then size(), and max-height is set to the space available on the side it picked. When the list first opens it is too tall for the side below, so it flips above. A query that matches little shrinks the list enough to fit below, so it flips there. When the query is cleared, size() has already capped it to the space below. Nothing overflows, so flip() never moves it back.

Changes

• filter-dropdown.tsx: "Clear all" prevents the close. It moves focus before the item unmounts: to the search box if there is one, otherwise to the menu.
• select.tsx: once a query starts, SelectContent reads the side it was placed on (data-side). It then passes that side back with avoidCollisions={false} until the select closes. The lock lives in Select's context and is cleared when the select opens. With avoidCollisions off, Radix also stops shift(), so while locked the list isn't nudged sideways back on screen. That only matters for a select at the very edge of the viewport.
• New tests: "Clear all" keeps the menu open and moves focus to the right place, with and without search. Both fail without the fix. jsdom has no layout, so the side lock can't be unit-tested; it was checked in the browser (see below).
• 4.3.2, with a CHANGELOG entry.

Verification

• pnpm format:check, pnpm lint, pnpm test (40 passing), pnpm build.

• In Studio, with this build in place, measured with Playwright in the Apply Policy dialog. Each cell is the list's side and height:

  Viewport	Open	No matches	Cleared
  1280×900, before	top, 524px	bottom, 99px	bottom, 317px
  1280×900, after	top, 524px	top, 99px	top, 524px
  1280×560, after	top, 354px	top, 99px	top, 354px

• In Studio, "Clear all" on the policy type filter inside the dialog leaves the menu open with every filter cleared. Focus is on the menu and no focus ring appears on the dialog.

🤖 Generated with Claude Code