[DataObject] [Classification Store] Fix selection modal: grid does not use full modal width and columns are not resizable

[albertmueller]

Description

In the ClassificationStore selection modal (opened from the DataObject edit view when adding
a Collection/Group/Key to a classificationstore field), the selection grid in all three tabs
("Collection", "Gruppe"/"Group", "Nach Schlüssel gruppieren"/"Group by key") renders at a fixed
width far narrower than the modal itself, and its columns cannot be resized by dragging the
column border — unlike virtually every other grid in Studio (e.g. Predefined Properties,
Translations, Document Types).

Steps to reproduce

1. Open any DataObject with a classificationstore field in Studio.
2. Go to the field's "Attribute" tab and click "Hinzufügen" / "Add".
3. Observe the selection modal: the grid only fills roughly the left third of the modal width,
   with a lot of empty space to the right.
4. Try to drag the border between two column headers to resize a column — nothing happens.

Expected behavior

• The grid should fill the full width of the modal (as it does with autoWidth elsewhere).
• Columns should be resizable via drag, consistent with other Studio grids.

Actual behavior

• The grid renders at the sum of TanStack's default column widths (150px each), leaving most
  of the modal empty.
• Columns are not resizable.

Root cause

ClassificationStoreDataTab and ClassificationStoreCallbackTab
(src/core/modules/element/dynamic-types/definitions/objects/data-related/components/classification-store/components/classification-store-modal/components/classification-store-data-tab/)
render their <Grid> without the resizable and autoWidth props. Both props are required for
Grid to enable column resizing (Resizer) and full-width layout — see
src/core/components/grid/grid.tsx. Every other grid in the codebase that wants full-width /
resizable behavior sets both props explicitly (e.g.
src/core/modules/predefined-properties/table/table.tsx).

Environment

• pimcore/studio-ui-bundle 2026.2.x
• Pimcore 2026

Fixes pimcore/platform-version#304

A fix is ready: adds resizable/autoWidth to the two <Grid> usages and sets explicit column
sizes with one autoWidth column per tab (Collection/Group/GroupByKey), so the last column fills
the remaining space. PR will follow from branch fix/classification-store-modal-grid-width.

Fixed state:

Fixes pimcore/platform-version#304

[Copilot]

Pull request overview

Fixes classification-store selection grids so they fill the modal width and support column resizing.

Changes:

• Enables autoWidth and resizable on shared selection grids.
• Adds stable column definitions with explicit sizes and one flexible column per tab.

Reviewed changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tabs/group/group-tab.tsx	Adds sized, flexible group columns.
tabs/group-by-key/group-by-key-tab.tsx	Adds sized, flexible key columns.
tabs/collection/collection-tab.tsx	Adds sized, flexible collection columns.
components/classification-store-data-tab/classification-store-data-tab.tsx	Enables full-width, resizable grids.
components/classification-store-data-tab/classification-store-callback-tab.tsx	Enables full-width, resizable callback grids.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
55.6% Duplication on New Code

See analysis details on SonarQube Cloud

[kingjia90]

Verified against the Grid component API and all call sites:

• autoWidth / resizable are real Grid props (grid.tsx:60, grid.tsx:250) and the per-column meta: { autoWidth: true } fill-pattern is the same one used by other Studio grids (e.g. saved-searches tab) — this brings the CS modal in line with the rest of Studio.
• The one-autoWidth-column-per-grid validation in grid.tsx (validate if only one column has autoWidth) is respected: each tab defines exactly one flexible column.
• The two shared renderers (classification-store-data-tab.tsx, classification-store-callback-tab.tsx) are only consumed by the three updated tabs (collection / group / group-by-key), so no other grid picks up the new behaviour unintentionally.
• useMemo on the column defs with [t] is correct and now actually load-bearing, since the grid's autoWidth validation memoizes on column identity.
• Copilot: no findings. CI green (build, lint, types, Codeception, PHPStan, Sonar).

I added Fixes pimcore/platform-version#304 to the description so the issue-link guardrail passes and the issue auto-closes on merge.

[ValeriaMaltseva]

@albertmueller
Hi! I really appreciate your help. Thanks! :)
I'll merge the PR.