Sometimes you'd want a certain block displayed as a single column an others displayed per element in the entities by column. This could for example be a budget for the year and than the actuals by month. The way we have always achieved this is kind of an awkward work-around. For the block that should be a single column we have enabled "Detail by" with an entity, which has only one element. This work-around, however has some disadvantages and it would be much nicer to be able to check an option like "display as single column" or "exclude from column entity".