In a recent commit, the kanban view was changed to display a nocontent
help message, even when grouped. To do that, it was necessary to change
the nocontent structure, and in particular, to position it absolutely.
This totally breaks dashboards.
Also, from a functional point of view, dashboards are used to see
existing information, so it can be said that the nocontent helper is of
a more limited use in this case. Therefore, I think that the best
technical decision is to simply remove the nocontent helper in the
dashboard, rather than fiddling with the css to try to make them work.