The member 'DynamicFlatTreeDataGridSource<TModel, TModelKey>.Dispose()' does not hide an accessible member. The new keyword is not required.

Non-nullable property 'ColumnStates' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Dereference of a possibly null reference.

Dereference of a possibly null reference.

The member 'DynamicFlatTreeDataGridSource<TModel, TModelKey>.Dispose()' does not hide an accessible member. The new keyword is not required.

Non-nullable property 'ColumnStates' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Dereference of a possibly null reference.