How to disable middle mouse button to change to pan mode

As a default behavior, the middle mouse button changes the mouse scroll to zoom in/out to pan modes.

What is the best way to disable this? We would only like the mouse scroll to zoom (no panning).

Thanks in advance.

Presumably you have already set ToolManager.mouseWheelBehavior to `go.ToolManager.WheelZoom. In addition, you could override ToolManager.doActivate to force the wheel behavior to be zoom.

      $(go.Diagram, . . .,
            . . .,
            "toolManager.mouseWheelBehavior": go.ToolManager.WheelZoom,
            "toolManager.doActivate": function() {
              this.mouseWheelBehavior = go.ToolManager.WheelZoom;
            . . .

[EDIT] Oh, I see you have discovered the same solution that I just rediscovered: How can I cancel the default middle click event?