DataPointSelectionModifier

Good questions

Making the modifier source open is not a problem however splitting up packages in the library is the challenge here – sharing or open sourcing the modifiers without making it a breaking change and managing versioning for maintenance.

If you set the property DataPointSelectionModifier.AllowsMultiSelection = false this will disable both rectangle and ctrl multi select.

Next, you will need to override GetSelectionMode() to change the behaviour.

    // Inherit DataPointSelectionModifier & override GetSelectionMode
   // This is OUR implementation
    protected virtual SelectionMode GetSelectionMode(MouseModifier modifierKey, bool isAreaSelection)
    {
        var selectionMode = SelectionMode.Replace;

        // Remove this if block 
        if (!AllowsMultiSelection)
        {
            return selectionMode;
        }

       // Change behaviour here to return SelectionMode.Union, Inverse or Replace depending on what you want
        if (modifierKey == MouseModifier.Ctrl)
        {
            selectionMode = isAreaSelection ? SelectionMode.Union : SelectionMode.Inverse;
        }
        else if (modifierKey == MouseModifier.Shift)
        {
            selectionMode = SelectionMode.Inverse;
        }

        return selectionMode;
    }

So long as the above returns SelectionMode.Union, even if AllowsMultiSelection is false, the modifier should let you CTRL click multiple points.

Does this help?

Best regards,
Andrew

Thank you Andrew, I’ll give that a shot.

If it is tricky to make the live version opensource, maybe you could just opensource the current version as it stands now as copy into an example project (i.e so you don’t have to maintain it), it would still be super helpful to understand how everything hooks up.