Scroll Shadow Indicator

Show people that a panel or table has more content past its edge.

moderate User Experience

What it adds

Edge shading on scrollable containers that appears only on the sides where content continues.

What your agent is told to do

1
Find the containers that scroll independently of the page — tables, side panels, dialog bodies, tab strips, code blocks — and give each an edge treatment that appears only where content continues past that edge.
2
Recompute the indicators whenever the scroll position moves, the container resizes, or the content changes. A shadow that was correct at first render is wrong the moment a row is filtered out.
3
Handle both axes. A wide table needs left and right indicators far more urgently than top and bottom, because horizontal overflow is the kind users are least likely to guess at.
4
Draw the indicator so it never sits on top of a sticky header, a frozen first column, or a pinned action row. Those elements own their edge, and a shadow over them reads as a rendering fault — take the offsets from Safe Sticky Positioning rather than guessing at heights.
5
Do not leave a permanent shadow on every scrollable container. An indicator that shows when there is nothing more to see teaches users to ignore it, which defeats the whole point.

Edge cases it handles

Content that loads late, a filter that removes rows, or a section that expands all change whether overflow exists, so the indicators must be driven by live measurement rather than computed once when the container mounts.
A container that scrolls on both axes needs four independent indicators, and the corner where two of them meet must not double up into a dark blot.
A shadow drawn over a sticky header or a frozen column looks like a smudge rather than an affordance; the indicator has to sit beneath the pinned content or begin below it.
Containers whose content fits must show nothing at all, including during the moment they briefly overflow while a resize is in progress.
The indicator is decoration and must be invisible to assistive technology and transparent to pointer events. A shadow that swallows a click on the first row is worse than no shadow.
Forced-colours and high contrast modes drop shadows entirely, so a container relying on one alone gives no hint of overflow — pair it with a border or accept the loss deliberately.
Measuring on every scroll event in a long table is expensive; sample the position rather than forcing a layout calculation on each frame.

Definition of done

Every independently scrolling container indicates its edges only where content continues.
Indicators update on scroll, on container resize, and when the content changes.
Horizontal and vertical overflow are both indicated, including in containers that scroll on both axes.
No indicator overlaps a sticky header, frozen column, or pinned row.
Containers with no overflow show no indicator at all.
Indicators receive no pointer events and are not announced to screen readers.
Overflow remains discoverable in forced-colours mode.
The feature matches the existing design system.
No existing functionality is broken.

Related features

Feedback Widget

Interactive Transcript

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How it works

1

Copy the link

Grab the Markdown instruction URL for this feature.
2

Give it to your AI

Paste it into Claude Code, Cursor, v0, Lovable — whatever you build with.
3

It inspects, then implements

Your agent reads your existing app first, then adds the feature to fit it.

Works with your stack

These instructions are written to adapt. They tell the agent to detect your framework, match your existing design system, and reuse what you already have — rather than assuming a particular stack.

Need it tighter than that? Customize the feature and tell it exactly what you're running.