NOTE: Apologies for the very small font in the screenshots. Please click on a screenshot to display it in a bigger format. :)
1. With a red minus sign at the left, with line numbers 1 and 3 visible.
2. If I click the red minus sign, it changes to a red plus sign, and I now see lines 1, 2 and 3.
I've attached the file (filename scrubbed).
Also (this issue may or may not be related): The JS program code displays with no line breaks. (That's how it came down from the site.) Can this issue be remedied? (If you experts feel this issue should be a separate question, please let me know and I'll be happy to comply.)