I'm not sure what you mean with 'the context will save the data'.
If you close a dataview without properly saving or rollbacking it, the changes will stay in your cache as that is where the changes are cached until they are committed. As these are not committed yet, no events or refreshes will be triggered in your datagrid.
I mean It is confused that without saving the data and going to another page or even refresh , the data stays at the data view . and this is considered as strange behavior in the web applications. because the context is divided into many levels as page,request,session, and application, but i think mendix use only the session context(so the data will be cleared just if the session is lost as if I signed out(lose session context) or restating server(lose application context ). while in this case if the context is tied to request,it will clear unsaved data at this data-view.