Is it possible to add widgwt into widget?

I use kentico 12 mvc application. I have my own page type. I succesfully added "Widget 1" on this page. Then I try to add "Widget 2" into "Widget 1". In page builder all is ok, but when I try to save I get error: "Areas with the following identifiers are missing from page markup: area2. Saving the page will result in lost data". In body of my page type view I have: @Html.Kentico().EditableArea("area1"). And in body of "Widget 1" view: @Html.Kentico().EditableArea("area2")