About the UI Element

This element is read by the UI engine to determine the layout of the user interface. Only linear layouts are supported. The UI tag is for grouping purposes only. There are no attributes associated with this tag.

The UI element has these children:

Child	Description
`Container`	A tab that contains any options for the task. For example, you might want to display the option for selecting the input data and assigning columns to roles on the same page. The UI engine displays these options sequentially. A label is created for the tab. The `Container` tag takes only one attribute. The string for this option is the value of the `string` input type in the `Metadata` element.
`Group`	A title for a group of options. The UI engine displays these options sequentially. This tag takes these attributes: The `option` attribute is an option name in the metadata. This string is the same as the string value for the metadata option. The `open` attribute specifies whether a group is expanded or collapsed. By default, `open=false`, and the group is collapsed in the user interface. To display the contents of a group by default, specify `open=true`.
`DataItem`	A reference to an input data source. This tag has only one attribute. The string for this option is the value of the `string` input type in the `Metadata` element.
`RoleItem`	A reference to a role. This tag has only one attribute. The string for this option is the value of the `string` input type in the `Metadata` element.
`OptionItem`	A reference to an option that has a single state. This type of option is either on or off, or has a single value (such as a series of radio buttons). This tag takes the `option` attribute only. The `option` attribute refers to the metadata name attribute for the option. The string for this option is taken from the metadata string value.
`OptionChoice`	A reference to an option that has a choice of values. The `OptionChoice` element uses the `OptionItem` or `OptionValue` element to represent the choice of values. These input types can use the `OptionChoice` element in the user interface: `combobox` `distinct` `multiedit` `select` This tag takes the `option` attribute only. The `option` attribute refers to the metadata name attribute for the option. The string for this option is taken from the metadata string value.
`OptionValue`	A value choice. This tag is valid only as a child of the `OptionChoice` element.