Lock the first column of a data table

[tylercschneider]

One Sentence Summary

A developer building a wide table can lock its first column, so a person scrolling sideways still sees which row they are on.

ACs Covered

• A table whose first column is marked locked keeps that column's header and cells in view while the rest of the table scrolls sideways.
• A column marked locked that is not the first column is rendered as an ordinary column.
• A locked column has no checkbox in the column picker, so it cannot be hidden.
• A table with no locked column renders exactly as it did before.
• The README describes how to lock the first column.

Decision Log

How is a locked column kept out of hiding and reordering?

A locked column counts as not hideable everywhere a table checks, chosen over leaving it out of the Columns menu alone.

Code Example

Keystone::Ui::Column.new(key, header_text, mobile_hidden: false, sortable: false, hideable: false, locked: false)

Out of Scope

• Using the locked column on the revenue projection page is a later unit of the same feature, in the host app.

Ticket Billed Against

Not specified.

Tokens Used

• Input: 48
• Output: 8,464
• Cache read: 1,742,112
• Cache write: 226,573
• Total: 1,977,197

Effort

• Sessions: 3
• Prompts: 3
• Words typed: 1,526
• Pasted blocks: 0
• Words pasted: 0
• Questions answered: 0
• Interruptions: 0
• Rejected tool calls: 0
• Claude working time: 0m
• Your active time: 0m

Closes #297

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Generation Metadata

Scribe: pr-scribe 4aa2edc
Rules: pr-body 4aa2edc, draft-reading 4aa2edc, writing-style 4aa2edc
Model: claude-opus-5-5, cc 2.1.291