Nano: backspace causes IllegalStateException

[mattirn]

Move the cursor in the upper left corner in edit area and hit backspace causes IllegalStateException:

java.lang.IllegalStateException
	at org.jline.builtins.Nano$Buffer.computeCursorPosition(Nano.java:840)
	at org.jline.builtins.Nano$Buffer.getDisplayedCursor(Nano.java:810)
	at org.jline.builtins.Nano.display(Nano.java:2386)
	at org.jline.builtins.Nano.display(Nano.java:2360)
	at org.jline.builtins.Nano.run(Nano.java:1458)
	at org.jline.builtins.Commands.nano(Commands.java:115)
	at org.jline.example.Example.main(Example.java:424)