class − name of a controller class.

messagesPack − a default message pack for the screen. It is used to obtain localized messages in the controller using getMessage() method and in the XML descriptor using message key without specifying the pack.

caption − window caption, can contain a link to a message from the above mentioned pack, for example,

caption="msg://credits"

focusComponent − identifier of a component which should get input focus when the screen is displayed.

lookupComponent – mandatory attribute for a lookup screen; defines the identifier of a visual component that the entity instance should be selected from. Supports the following types of components (and their subclasses):

datasource – mandatory attribute for an edit screen which defines the identifier of the datasource containing the edited entity instance.

metadataContext − the element initializing the views required for the screen. It is recommended to define all views in a single views.xml file, because all view descriptors are deployed into a common repository, so it is difficult to ensure unique names if the descriptors are scattered across multiple files.

dsContext − defines datasource for the screen.

actions – defines the list of actions for the screen.

timers – defines the list of timers for the screen.

companions – defines the list of companion classes for the screen controller.

layout − root element of the screen layout, a container with a vertical layout of components, similar to vbox.