The deleteLine function in editor doesn't work when the line number is zero and the line is null: i.e. the line length is 2 and the content is CR-LF (13, 10). When that occurs, the statement executes without an error but doesn't delete the line. It works OK when a null occurs on a later line and it's also OK when anything else is deleted from line zero.
OK, thanks for the detailed description. I'm planning on releasing 1.0.6
this weekend, so I'll try and fix that in with the changes.
Fixed in 1.0.6, just released :)
deleteLine actually had some weird logic that made it behave oddly in a few cases. It now does what you'd expect.
Thanks for the report!