Fieldset can be used to create a section with borders to neatly place controls into the layout.
FormInput is an advanced version of the Fieldset that renders a section with a label to place a widget into it. The FormInput control allows using any Webix widget as a form element. All elements are rendered with the same style, which helps to create a good-looking form.
Fieldset has only a few properties, it doesn't require any significant effort to configure Fieldset. Using the two main properties, you can complete most of the work: define the elements that will be placed within the Fieldset and set the text label for it. Optionally, you can set paddings or hide the component borders.
You can easily place any widget into a Form with the help of the FormInput. Wrapped in the Form Input, the widget will look like any other Form control. It is also possible to set the width of the label and choose its location - to the right or to the left of the control's container.