This is going to sound really odd to ask, but have you, by any chance, clicked the "Update" button next to the node list?
If you have, then it's going to cause issues. Because these are older configs that won't work. You will need to uninstall, then re-install the widget. I ran into this issue, and it took me a while to figure out what was going on. A bit of a nitpick to be sure, but, it's worth checking.