"attempt to index nil with FocusedDataModelSession" error with custom tab

Repro steps:

  • Download and place the following files in your %localappdata%/Roblox/<Your User ID>/CustomRibbonTabs folder:

Mini_{38b16910-2e07-4a66-ac47-4e2f826f014c}.json (10.7 KB)
RibbonLayout.json (1.2 KB)

  • Start Studio and attempt to click on any of the small buttons in the Mini tab

Expected behavior:
The actions work

Actual behavior:

Nothing happens, and an error shows up in the Output

First experienced: 27th September, 2025
Frequency: Always

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