Re: Power BI August 2026 Feature Summary

Thanks for the response DataZoe​ . I'm aware of the ability to control/select the base theme in the theme file, but the problem is the way in which it presents in the menu and the fact PBI now defaults to the new base theme (and new default page size) when creating a new document, so to future-proof both the theme file and future PBI file creation, I've had to update it to deal with the new base theme and reset the page size to the expected scale in the theme file, then rush release the theme file update to account for the new (file creation) default behavior. We were already planning for this so most of the work was already in place, but the fact it's been made GA while the default slicer is still reverted to list (vs. dropdown) is problematic and leaves us in a rather awkward situation with the style presets for the slicer, as they were built around the idea that the default would now be dropdown.

Also, a quick note to say I really appreciate that the 'custom default page size behaviour' has at least been fixed (so that it appears as a proper default now when specified in the theme file), that was really important for us, so thank you and the team for that!

Regarding the note about how it presents though, this is important because with the scale of our organization, 'new' PBI users/authors are coming 'online' all of the time, and not everyone is going to understand to not click this unless they remember being told not to do so:

This was a test I did just now to make sure the behaviour hasn't changed (which would have made some of my concerns null and void), but as you can see, unfortunately even if I specify an older base theme in the custom theme file, PBI still presents as though the base theme can/should be updated, rather than simply accepting the selected base theme as the new default, and suppressing the option to update the theme (which would be ideal).

I appreciate the language doesn't explicitly state that you need to update, and even warns it may introduce 'minor' changes to the report (although that's very subjective depending on the custom theme file/formatting options being used), but many people will just see 'Update theme' and click it instinctively as the implication is still there, hence we've instead made sure our theme file is compatible with the latest base theme to avoid any confusion and extra details to remember for users utilizing PBI.

Also, regarding this comment: We are working on getting the custom theme slicer mode set in the custom theme to apply correctly, but it would apply only when you create the slicer. 

Thank you for this, but just to clarify, are you still planning to have the default/regular slicer be in dropdown mode (when created) by default in the future? And if so, could you give a possible timeline please? I want to avoid switching around style presets because it would create havoc for report authors/editors in the future (I've tested this scenario extensively), but if I have a sense of when it will be updated I can at least give users a target date/timescale (even if vague) for when the current workarounds will no longer be necessary.