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I noticed with the new PowerApps release 3.19013.14, that there seems to be some syntax changes (or inconsistencies?) with regards to OptionSets. These following screenshots show the auto-generated properties for a single-select OptionSet field of a D365 entity, selecting Common Data Source App, choosing OptionSet field in EditForm1.Fields property, letting PowerApps do the rest. This doesn't seem to work and the Items property seems to be nonsense. Just setting the Items property to
I distinctly remeber that just some time ago, I could not use Choices for OptionSet, but only for MultiSelect-OptionSet and LookUp fields, but had to use something like