Performance issue when adding copied rows

[Zt-freak]

When repeatedly adding copied rows to a table, it causes performance issues. It appears this only happens when copying and adding alternate. When all rows are copied first and then added, this does not cause this issue.

Example code, which causes this issue:

Most likely the collection of visited objects contributes to this issue.

After adding the 6th copied row, visited contains more than 20000 records.

I'm using NPOI 2.6.0