Datavalidations performance issues during copying

[OssianEPPlus]

When copying data validations, EPPlus iterates all data validation items in the worksheet to see if the address matches the copied range this has devestating effects on performance when a high amount of dataValidations are present.

Workaround: Exclude dataValidations when copying cell by cell then add the addresses to the dataValidation ranges manually.

Use of quadtree could be a helpful starting point.