Steps to reproduce

I would like to add a red vertical bar on the left side of certain rows based on specific conditions. For example, if some rows within a group do not have an email available, I want to display a red bar at the beginning of those rows.

While this can be done in the master-detail view (where we can customize the detail panel toggle), this approach doesn’t seem to be possible with row grouping, as there isn’t a toggle column available for such customization.

Current behavior

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Expected behavior

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Context

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Your environment

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Search keywords: How can I add a class in expand panel in grouping?