Copying the field ignores anything above row 20

[Not-A-Normal-Robot]

If you can reproduce it, write the steps here. If you can't, try to describe what causes the unintended behavior, like pressing a key/button (Details Here):

1. Make a field that extends beyond row 20
2. Copy it
3. Paste it back
4. Your work beyond row 20 is gone :owhy:

[MrZ626]

*Then someone send a field of 1e10 lines to his friends*

[ImpleLee]

A more reasonable upper bound is of course better than 20.

[Not-A-Normal-Robot]

1 thousand should be a good upper bound ~~then I send 1e6 fields in custom game at 1e4 lines per field each, making a total of 1e10 lines~~