The introductory class notes for Ext.dataview.ListItem and Ext.dataview.SimpleListItem prominently mention the deprecated Ext.dataview.List.useSimpleItems

http://docs.sencha.com/extjs/6.5.0/m...eListItem.html
http://docs.sencha.com/extjs/6.5.0/m....ListItem.html

Instead they should refer to
http://docs.sencha.com/extjs/6.5.0/m...cfg-itemConfig
http://docs.sencha.com/extjs/6.5.0/m...fg-itemDataMap
(or probably the corresponding configs on Ext.dataview.Component )