source.mode "derived": `crossFilter` is not supported when `from` is a union of several grids - it has no single target once there is more than one parent. Push a filter onto the individual source grid you mean instead.

Warnings reference › source.derived.union.crossfilter

Identifier

source.derived.union.crossfilter

Raised by

The grid (core)

Since

1.51.0

What happened

Cross-filtering pushes a filter back onto the parent, and a union has several. The option does nothing. It is reported at construction rather than when crossFilter is first used, so that a host that configures it and never calls it still learns that the line has no effect.

The fix

Push the filter onto the individual source grid you mean.

Reference

Covered in full at the API reference.