Fretboard diagrams - multiple dots - open string
As of version 3.5.2, there is no way to combine Open String and Multiple Dots in Fretboard Diagram.
This use case falls under the same criteria as multiple dots for fretted strings: for either sequential playing or alternative fingerings.
This can be achieved if the Open String symbol "O" was treated the same way as a regular (fretted) dot, when it is applied with Ctrl. Currently, when Open String is applied (with or without Ctrl), any fretted dots are automatically removed.