User Data Functions, List Slicer, and Select All

Hi omnipotamus ,

Yeah, this is a known quirk with list slicers and user data functions in Power BI. When you hit "Select All," Power BI actually treats it as “none selected” in the backend, which breaks UDF submission (the button gets disabled). There’s no native fix—users have to manually pick items.

Workarounds people use:

• Tell users to select all items manually (not ideal, I know).
• Sometimes you can pre-select all but one, save that as default, and instruct users to add the last one, but it’s clunky.
• No way right now to use "Select All" and have it behave as expected with UDFs.

For your second question:
If you add multiple fields to the list slicer, it stops supporting UDFs—this is also a current limitation. Only one field in the slicer works with user data functions.

Not perfect, but that’s the state of things. If you want, you can add an idea in the Power BI forums for better support!

Let me know if you want help with any specific workaround.
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