Widgets menu has disappeared and front page edit shows blank


M y widget menu disappeared in some point (not exactly sure when). It's theme related, because even when disabling all the plugins it doesn't show but when changing themes to any of the wordpress stock ones the menu items show again.

Second problem is that I can't edit frontpage anymore, it only shows blank. Other pages work fine. Also, I would like to have the frontpage shown in the Upfront pages list, now I always have to navigate to the frontpage and then click "Upfront".

Text problems are still an issue, any idea when a fix/update to Upfront is available?