This is more of a very long standing feature rather than a bug but Spinner has a Prompt property that I don't think can ever be used because Spinner in B4A is only ever used in dropdown mode and I think the prompt is only used in dialog mode.
I use SelectedItem=0 of my Spinner list as my Prommt text. Maybe I don't use .Prommt function correctly, because when I try to use it, it does not appear.... I tried to find an example using prommt, but didn't find. Can someone give me an example of prommt use in B4XCombobox or is it possible...