config.gallery is on but the grid has no columns and no template, so a tile would draw nothing. Supply gallery: { template: '<div>{{cell.name}}</div>' } or add columns.

Warnings reference › gallery.empty

Identifier

gallery.empty

Raised by

The grid (rendering)

Since

1.19.0

What happened

The gallery presentation builds a default tile template from the grid's columns when it is given none, and there are no columns either - so every tile would be empty. The presentation is refused and the grid stays a table.

The fix

Give the gallery a template, or declare the grid's columns.

Reference

Covered in full at the API reference.