I had a functioning Lightswitch application built with VS2012RTM. It was interacting with a RIA service backend. Recently, the RIA Service assembly was 'upgraded' to use DbContext instead of ObjectContext, breaking the lightswitch application.
So, I created a new datasource in Lightswitch to source from the SQL Server, and switched all of the screens over to the new datasource. Then, I did an 'upgrade project' in Visual Studio to Update 2. Now, none of my screens are editable. Nothing about the internal permissions changed, only the datasource and login (which has all the rights it needs) and the version of Lightswitch.
Any clues?
Apparently, new screens must be created against the new data source. What I had attempted to do was add Data Items from the new data source to the existing screens, wire up to the new data, and then delete the original Data Items from the screen. Creating the screens from scratch was the only way I could get them editable again.