In Alloy demo site, in DisplayRegistryInitialization 3 display options has been added to ServiceLocator.Current which tells Episerver to show those 3 options for all blocks. However, for some blocks we only have 1 or 2 of those options available, like on JumbotronBlock (look at TemplateCoordinator).
As a result, the editor can select an unavailable option (like "narrow" for JumbotronBlock) and end up with a "The 'JumbotronBlock' can not be displayed" message not knowing what is worng.
Is there any way to limit display options for each individual block type?