I've found another two issues.
I can't find the dataMap config variable in config explorer for Ext.dataview.component.DataItem component and I can't add it as custom property due to existing reservation in architect.
Ext.dataview.component.DataItem is not dropable into views in project explorer. I can drop it only to the top level in UI designer (I mean device frame) what places it to the views project category.
I'm using SA2 build 442.