UnregisterBehaviour bug

[toczekmj]

Hi.
Today I've experienced weird bug related to overwriting existing selection behavior.
Our app seems to work fine while using default settings (example below)

Working.edited.-.Made.with.Clipchamp.mp4

But when we overwrite selection behaviour either with the default one, or with custom implementation, cards starts to behave unexpectedly. Namely in order to move a particular card we need to double click it, otherwise previously selected card is being moved. Example below:

Not.working.edited.-.Made.with.Clipchamp.mp4

This os our diagram configuration (working version, without overwriting default behavior)

var options = new BlazorDiagramOptions
        {
            LinksLayerOrder = 10,
            NodesLayerOrder = 10,
            AllowMultiSelection = true,
            Zoom =
            {
                Enabled = true,
                Minimum = 0.3,
            },
            Links =
            {
                DefaultRouter = new NormalRouter(),
                DefaultPathGenerator = new SmoothPathGenerator()
            },
        };

        var diagram = new BlazorDiagram(options);

And this is the overwriten version:

var options = new BlazorDiagramOptions
        {
            LinksLayerOrder = 10,
            NodesLayerOrder = 10,
            AllowMultiSelection = true,
            Zoom =
            {
                Enabled = true,
                Minimum = 0.3,
            },
            Links =
            {
                DefaultRouter = new NormalRouter(),
                DefaultPathGenerator = new SmoothPathGenerator()
            },
        };

        var diagram = new BlazorDiagram(options);
        diagram.UnregisterBehavior<SelectionBehavior>();
        diagram.RegisterBehavior(new SelectionBehavior(diagram));

It seems like some event is not being disposed while unregistering the behavior, but we really have no idea what is going on. Hope someone will help us.

[toczekmj]

@FlaviusAugustus

[zHaytam]

Hello, I will check this out!

[zHaytam]

Hey, I found why this happens:

• SelectionBehavior is the first behavior registered in the diagram by default
• The others, such as DragMovablesBehavior come after
• The drag movables one moves the selected node, but the selected node is decided by the selection behavior

When you add back the selection behavior last, its events are AFTER the drag movables on, which means that it will try to move the previously selected element and then select the newly clicked one.

To fix this, I have added a new parameter in the constructor of BlazorDiagram:

var diagram = new BlazorDiagram(options, registerDefaultBehaviors: false);
diagram.RegisterBehavior(new SelectionBehavior(diagram)); // or yours
diagram.RegisterBehavior(new DragMovablesBehavior(diagram));
diagram.RegisterBehavior(new DragNewLinkBehavior(diagram));
diagram.RegisterBehavior(new PanBehavior(diagram));
diagram.RegisterBehavior(new ZoomBehavior(diagram));
diagram.RegisterBehavior(new EventsBehavior(diagram));
diagram.RegisterBehavior(new KeyboardShortcutsBehavior(diagram));
diagram.RegisterBehavior(new ControlsBehavior(diagram));
diagram.RegisterBehavior(new VirtualizationBehavior(diagram));

For now this should unblock you, but I'm not very happy with the fact that users need to know all the default behaviors and their orders, I'll see if I can think of a better solution or maybe you guys have a suggestion!