The only way to edit simple notes is via the properties window.

The ordinary way (at least the way I've done it for years) is the right mouse button click edit, but this causes the

disappearance of the cursor from the working area and whatever I've tried the only way back is save-close-restart-reload.

I'm working on a free DS 2017 W64 version SP1 with the recent Hotfix 2/17 applied.