Previously, if someone grouped data in the grid by a property that was not available for all visible models, we used to abandon the grouping, show an error, and then load the category grouping. In order to prevent this from happening, we have design "Tolerant Grouping"
Tolerant Grouping would allow users to choose any property of any visible model as a grouping property, and where a model does not have that property, group all those objects into a grouping of "Not applicable" or "Not assigned". Moreover, in the grouping edit dialog Assemble offers a union of properties available in any visible model.
In the case someone attempts to load a grouping that has properties which are not in ANY currently visible model, Assemble allows the user to edit those properties in addition to the union of the visible model properties, and indicates that these unavailable properties are not available in any visible model. This allows Assemble users to load any grouping for any view, and therefore solves the issues around being able to delete or edit any grouping at any time.
In Tolerant Grouping, when grouping the Grid by a property that does not exist in at least one visible model, or does not exist in any visible model, grouping row header will be "Not Applicable" for all objects within that model.
Also, when editing a grouping, Assemble will show you a warning if a property does not exist in at least one visible model.