Modeling conventions for the screen design

In a screen design, only one single root element is allowed to exist in the layout column of the model. The object occurrence must not have an incoming connection of the contains type.

Root elements

Root elements allowed include:

Circular dependencies must not occur between elements that are linked via a connection of the contains type.

Example

If element A contains element B, and element B contains element C, element C cannot contain element A.

Subordinate elements

Every subordinate element may be linked to only one single superior element via a connection of the contains type.

A subordinate element must be placed entirely within its superior element. Elements must not overlap, except if they are linked via a connection of the contains type.

Every element is allowed to have specific subordinate elements only:

The Combo box (ST_COMBOBOX) and Drop-down list box (ST_DROPDOWN) elements may have only elements with an indirect dependency. These elements serve as containers for a selection. The selection is specified in the Full name attribute as a semicolon-separated list.

The following elements can have no dependent elements: