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Question for going forward - Is the showcase app like to expand? As in, how likely is it that over time more and more fields will be added. If this is the case, then it might be worth considering adding Categories for the Form Field tab control list. For example Text, Button etc. The question then is whether to list by control type ('Text fields') or functional type (Text inputs) which include ('Text fields'). Vaadin mix these in their documentation, probably a sensible approach.
Examples:
Form fields tab changes
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