Click-to-add-to-set interaction for dynamic comparison across charts

What is the problem or goal you're trying to solve or accomplish?

There is no way to click a mark in a chart and dynamically add it to a comparison set that drives other charts on the dashboard. Users who want to compare a selected subset of data against the rest have no direct interaction model for this.

How are you solving it currently?

A partial workaround exists using virtual datasets that model IN/OUT set membership combined with Jinja filter_values() macros, but this requires significant dataset modeling effort and is driven through the filter panel — not by clicking a chart mark directly. It is not a viable solution for most users.

What is your recommended solution?

Add a click interaction on chart marks that allows users to add or remove data points from a named comparison set. This set would then be available as a filter/dimension across other charts on the same dashboard, enabling dynamic "selected vs. rest" comparisons without requiring manual filter panel configuration.