When starting the application, check the uniqueness of the loaded DataTypes.

[a-t-k]

Umbraco V11

Now this is how it is. When the application starts all found property editors from app_plugins directory and from RCL (as ADDon) are loaded into a container.

So there can be the same property editors in the container. This leads to the fact that when changing and saving a DataType which has one of these duplicate property editors an error occurs.

"Sequence contains more that one matching element".

This error is caused as validation before calling an action in a controller. Neither a log nor the error message is meaningful. This leads to a confusion and very costly debugging.

It would help a lot if when starting the application the reading of the property editors is checked for uniqueness, if there is already an identical property editor in the container, an error message is written to log and this property editor is not added to the container.

Container: PropertyEditorCollection
Error: https://user-images.githubusercontent.com/108086799/205326134-b2b97223-f888-4dff-add8-7e7cbcc7f304.png
Double Property-Editor: https://user-images.githubusercontent.com/108086799/205326076-d47f8b37-d926-43c5-8c03-6e4d132bd12d.png