# Set control updates to observe context

> This is content from just-tim, the data-and-analytics channel by Tim Ngwena (formerly 'Tableau Tim'). Tim has 12+ years of hands-on BI experience and covers Tableau most of all, plus Power BI, Looker, Hex, SQL and data modelling, the analytics industry, and the craft of doing the job — always tool-agnostic and honest about the trade-offs.

- **Author:** Tim Ngwena (just-tim, https://just-tim.com/about)
- **Published:** 2020-08-12
- **Format:** Video · 4 min watch · transcript available
- **Topics:** Data visualisation
- **Tools:** Tableau (filters, parameters, sets)
- **Canonical:** https://just-tim.com/posts/set-control-updates-to-observer-context-in-tableau-2020-3
- **Watch:** https://www.youtu.be/aUwPeJ8sG7c

I demonstrate a Tableau 2020.2 enhancement where set controls now observe context. Using Superstore Sales, I show how adding a category filter to context changes the set control list so users can only select values currently in view, and I explain why this happens via Tableau's Order of Operations.

## Key takeaways

- From Tableau 2020.2, set controls can be made to observe context rather than showing all values in the database
- Adding a dimension filter to context and choosing 'all values in context' on the set control restricts the list to what's actually in the current view
- Tableau's Order of Operations runs extract, data source, then context filters before sets are computed, which is why sets previously ignored downstream filters
- This is a niche fix that mainly matters if you use sets heavily, and it tightens up control over what users can select

## Chapters

- 0:17 Building a simple set control view
- 1:18 Set control ignoring context
- 1:47 Making the set observe context
- 2:25 Order of Operations explained
- 3:29 Why it matters in practice

Watch the full video, read the transcript and use chapter deep-links on the page: https://just-tim.com/posts/set-control-updates-to-observer-context-in-tableau-2020-3

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just-tim — Data and analytics, with a point of view. · https://www.youtube.com/channel/UC7HYxRWmaNlJux-X7rNLZyw · https://twitter.com/TableauTim · https://www.linkedin.com/in/timngwena