Reproduce:

1. New Document
2. paste a multi-line block of text in 1st pane
3. focus 2nd pane by clicking approx. centre
4. paste identical block in 2nd pane
5. result = a 'phantom' line is added to the 2nd pane

Note: problem does not occur if 2nd pane is focused by clicking on top or bottom line.

Version: 2.16.47b