2026 Week 15 | Power BI: Exploring and Enhancing the new Theme

/ Power BI, Workout Wednesday / By

Introduction

In this week’s challenge we are exploring the new Power BI Theme that is in Preview :

https://powerbi.microsoft.com/en-us/blog/deep-dive-into-modern-visual-defaults-and-customizing-theme-improvements-preview/

 

The new theme comes with new chart defaults and additional Style Presets.

 

The challenge is to set your own defaults by downloading the JSON Theme file and modifying it.

 

You can use a number of tools to help you achieve this – recommended tools are :

Visual Studio Code to view the JSON theme (NotePad++ is an alternative), Gmbh Theme Generator as a UI to help set defaults, and your choice of LLM.

Ideas for the challenge :

  • Line chart defaults from smooth to linear
  • Page alignment to top
  • Adjust the Filter Pane colours and interactivity to appear more like a button slicer (background to the canvas colour (grey), filters applied to blue). Optional : Add a bookmark button on the report page to hide and show the filter pane, like you would a hidden slicer panel.
  • Create Style Presets for the Textbox:
    a) Page Header – bold, size 18 font
    b) Callout Box – add a border and background
  • c) Main Body – Size 11 black font, no borders or background
  • Change Table Default to “Grow to Fit”
  • Change the sentiment colours and add your own icons to match

The full report theme JSON schema can be viewed here : https://github.com/microsoft/powerbi-desktop-samples/tree/main/Report%20Theme%20JSON%20Schema

Like the new Power BI Theme?  Make sure you drop feedback! 

Modern Visual Defaults (Preview) Feedback form.

Happy Vizin’

Kez

Requirements

  1. Open Power BI Desktop March 2026 onwards. Enable new Power BI Theme Preview
  1. Use the sample Data available from Desktop or your own data
  2. Start building a report to explore the new style defaults
  3. Begin Modfying the Theme File and Download the Theme JSON File
  4. Navigate to GMBH or a Theme File Explorer of your choice. And Upload your JSON Theme File
  5. Set line chart defaults from smooth to linear
  6. Set page alignment to top
  7. Adjust the Filter Pane colours and interactivity to appear more like a button slicer (background to the canvas colour (grey), filters applied to blue). Optional : Add a bookmark button on the report page to hide and show the filter panel (activating/deactivating the eye button), like you would a hidden slicer panel.
  8. Create Style Presets for the Textbox:
    a) Page Header – bold, size 18 font
    b) Callout Box – add a border and background
    c) Main Body – Size 11 black font, no borders or background
  9. Change Table Default to “Grow to Fit”
  10. Change the sentiment colours and add your own icons to match
  11. Open the newly modified theme file in Desktop to view it
  12. Share your Feedback!

Dataset

This week’s dataset is downloadable from Our World in Data here

Share

After you finish your workout, share on Bluesky or LinkedIn using the hashtags #WOW2025 and #PowerBI, and tag @MMarie, @shan_gsd, @KerryKolosko. Also make sure to fill out the Submission Tracker so that we can count you as a participant this week in order to track our participation throughout the year.

Solution

Via Data Stories Gallery 

Coming soon.