Display an error message instead of the form when required information failed to load. In my opinion it does not make sense to display a form, e.g. when add a pool, the erasure coded profile or the list of OSDs failed to load. Currently the form is displayed, but the erasure coded profile combobox is displayed with no selectable entries, so the user will never be able to fill out the form correct and submit it. To better visualize that an error message should be displayed. This should be done for all form that load additional data.