Thank you Chrystl for the reply.
My widgets are all already defined to only appear for a single language but they still appear under the strings for translation. Maybe because the exsisted in the system before polylang installation? Should I reset/clear something in Polylang options for these string to be removed?
In the meantime, a workaround I found is to filer the displayed groups. This way I can save strings from groups other than widgets to the DB without corrupting the text widgets.
