linkki calls setComponentError on all fields bound to properties for which a message with the matching ObjectProperty exists. Vaadin then sets different CSS style classes depending on the ErrorLevel of the message, derived from its Severity. For example, a text field with a WARNING will have the style v-textfield-error-warning while a text field with an ERROR will have the style class v-textfield-error-error. These ErrorLevel specific classes are set in addition to a more general one just ending in -error such as like v-textfield-error.