I didn't review all the code changes in detail but tested it and works fine for me.
I wonder if we could make it visually more obvious that the directory and interval options belongs to the respective radio options. Maybe indenting them or wrap them in a `GtkFrame`?
i tried indenting blocks initially but rolled back because increase of overall height for this tab increases height for all of them. Both indentation and frame wrapping does not look ideal to me, but if we want we may use one or another. I committed indentation for now
