Crud, today it broke again. Still works to toggle Edit mode.
UPDATE: OK, additional detail to report -- works to extend wires UP, and insert blank rows, but not down (even if there is an empty row). Editor, Mouse tab in ladder section on maintain empty row vs. do not add has no impact. In either setting, Ctrl-Up works, Ctrl-Down does not, but Ctrl and Down Arrow both work individually.
I know this was some time ago. However, another customer reported this exact same behavior today via Automation Direct techs. We have not figured out what might be causing it. However, I can tell you, when I have the PC desktop app version of YouTube Music Player running, that app hijacks the Shift-Ctrl-Down and Shift-Ctrl-Up functions (Do-more delete down wire, delete up wire) for its volume control. So, perhaps there is an app running that is hijacking the Ctrl-Down for something?
I know Microsoft Excel uses it, and Microsoft Word, and most text editors, but, of course, these apps do not hijack it... instead when those apps have focus, the quick-key works. But I understand why YouTube Music Player hijacks it. You want to be able to change the volume of your player regardless of whatever else you are doing.
I'll post again if I discover, in this particular customer's case, what caused it.