Frozen Table Columns
Keep key identifiers visible while users scroll across wide data tables.
What it adds
Sticky leading or trailing columns that stay in place during horizontal scroll on a wide table.
What your agent is told to do
6
What your agent is told to do
6-
1
Compute each frozen column's offset from the measured widths of the columns before it, not from hardcoded numbers. One content change and fixed offsets are wrong.
-
2
Recompute offsets when column widths change — on resize, on column show or hide, on font load, and after data changes cell widths.
-
3
Define one explicit layer order for frozen cells, frozen headers, the sticky header row, row hover and selection states, and any menu opened from a frozen cell. Ad-hoc z-index values are where this feature usually breaks.
-
4
Keep header and body cell widths in sync from a single source of truth; two independently sized tables will never stay aligned.
-
5
Do not freeze more than a couple of columns, and disable freezing entirely when the frozen set would exceed roughly half the viewport width — the user is left with no scrollable area.
-
6
The small-screen strategy — which columns survive and the collapse to stacked cards — is owned by Responsive Data Tables; defer to it rather than defining a second mobile behaviour.
Edge cases it handles
6
Edge cases it handles
6- A shadow or border marking the frozen boundary must appear only while there is content scrolled underneath it.
- Virtualized rows must apply the same offsets as rendered rows, including rows recycled during fast scrolling.
- Row selection and hover backgrounds must cover frozen cells too, or the frozen column looks detached from its row.
- Menus and tooltips opened from a frozen cell must escape the scroll container rather than being clipped by it.
- Right-to-left layouts freeze from the opposite edge — do not assume the left.
- Keyboard navigation into a non-frozen cell must scroll it into view without hiding it behind a frozen column.
Definition of done
8
Definition of done
8- Multiple frozen columns align correctly at every scroll position.
- Offsets recompute on resize, column visibility changes, and font load.
- One documented layer order covers frozen cells, headers, hover, selection, and menus.
- Header and body widths stay synchronized during resizing.
- Freezing disables itself when it would leave too little scrollable width.
- Mobile behaviour is delegated to Responsive Data Tables.
- The feature matches the existing design system.
- No existing functionality is broken.
Related features
Weather Widget
Weather Widget
Show current conditions and a short forecast for a place your users care about.
What it does
A compact widget showing current conditions and a few days of forecast for a chosen location.
How it works
- 1 Add this as a tile in the app's existing Customizable Dashboard Widgets rather than as a fixed element bolted into a layout, so users who do not want it can remove it.
- 2 Fetch the forecast on the server on a schedule and serve the widget from the app's own cache. Calling the weather source from every visitor's browser leaks the credential and multiplies the request count by your traffic.
- 3 Show the observation time alongside the reading, and reuse the app's Stale Data Indicator conventions so ageing weather looks the same as any other ageing data in the product.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/weather-widget
Location Map Block
Location Map Block
Put an interactive map on a page showing one location or a whole list of them.
What it does
A reusable map block rendering one or many pinned locations, with a static fallback and a text address alternative.
How it works
- 1 The app already has Mapbox Geocoding and Google Places Address Lookup. Turn addresses into coordinates through the existing integration and store the result on the record; do not add a second geocoding path for this block.
- 2 Make the block take either a single location or a collection, and render the same component for both. A one-pin map is a collection of one, not a separate feature.
- 3 Reserve the block's height before the map initialises so the surrounding page does not jump when tiles arrive. The placeholder should occupy exactly the space the map will fill.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/location-map-block
Record Merge
Record Merge
Combine two duplicate records into one without losing anything attached.
What it does
A merge flow that picks a surviving value per field, reparents all related data, redirects old references, and can be audited afterwards.
How it works
- 1 Show the two records side by side, field by field, and require an explicit survivor for every field where they differ. Do not default to 'newest wins' silently; the user is merging because they know which one is right.
- 2 Reparent every related object — children, comments, attachments, activity, links, memberships — onto the survivor in a single transaction. A half-finished merge is worse than two duplicates.
- 3 Detect relationships that would become duplicates after reparenting (the same person as a member of both records, the same tag applied twice) and collapse them rather than violating a uniqueness constraint mid-merge.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/record-merge
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.