Does anyone have problems with their input list dropping the first column which shows a line number for each node pair? Without it, multiple lines can't be selected for block manipulation. Happens periodically to any file I open and lasts for hours or even days before it eventually corrects itself and ALWAYS at the most inopportune time. Any suggestions on how to correct this?

I notice it every once in a while. (Can't determine why.)
I believe it is there, just very narrow. Hover over that left edge of the window and try to catch that column and stretch it open.

I've noticed it too. It happens for some unknown reason, so I don't know what will prevent it from happening. But I know how to deal with it. Just drag the column out. Just like how you would resize any other column in the Elements list. Bring your mouse to the left most column header, and drag it to the right.

oh already answered. nvm.