B4J Question node type

You need to understand that complex nodes like the spinner are not base nodes, they are more like a superimposition of several nodes.
So any text based node will also be recognised as a textfield node, if it contains buttons as the spinner does, it will also be recognised as button, and so on, according to hierarchical position...

Not sure how you are creating the Spinner but I tested this and it is only recognised as a Spinner, not as a Textfield.

The code you posted for the if statement, it is impossible for it to be both. If it's a Spinner it won't even check if it's a Textfield.