Production checklist

Run this checklist before shipping a sheet family. It catches the failures that unit snapshots miss: ownership, scroll handoff, mobile viewport changes, focus, stacking, and visual end states.

State and actions

• Test controlled and uncontrolled open state.
• If snap is controlled, update it from onSnapChange.
• Confirm actions are enabled on the first paint; do not wait for animation state to make the trigger usable.
• Verify rapid open-close-open does not leave stale inertness or a backdrop.
• Verify programmatic close and gesture close produce the same final state.

Gestures and scroll

• Slow drag, fast flick, cancelled drag, and direction reversal.
• Scroll content to the middle: the sheet must not steal the gesture.
• Scroll to the dismissal boundary: the next outward drag must transfer naturally.
• Test mouse wheel, trackpad rubber-band, touch, keyboard paging, and scrollbar dragging.
• Confirm the native runway never becomes the visible product scrollbar.

Mobile viewport and keyboard

• Small phone in portrait and landscape.
• Browser chrome expanded and collapsed.
• Bottom safe area and Android navigation area.
• Focus the first, middle, and last input.
• Composer and primary action remain visible above the keyboard.
• Rotate or resize with the keyboard open.
• Close the keyboard without closing the sheet, then dismiss the sheet.

Accessibility

• Unique title and optional useful description.
• Enter, Space, Escape, Tab, Shift+Tab, arrow and detent controls.
• Focus enters the front sheet and returns to the correct trigger.
• Background is inert only for modal sheets.
• Alert dialogs cannot disappear through an accidental swipe.
• Reduced motion settles immediately without missing content.

Stacks and portals

• Open at least three ordinary sheets and ten Depth Sheets.
• Only the front layer reacts to Escape and outside interaction.
• Every underlying layer stays visually bounded.
• Third-party menus, date pickers, and tooltips remain interactive through ExternalOverlay.
• Closing several layers restores focus in reverse order without jumping to the page.

Performance

• Inspect the production bundle and import focused subpaths.
• Keep continuous travel work outside React state.
• Avoid simultaneous CSS and Velvet animation of the same transform.
• Check for layout reads in application callbacks.
• Confirm composition CSS is loaded once and in stable order.