i want to delete the selection on click of a context menu button
upon clicking this delete i get an error

i want to delete the selection on click of a context menu button
The GraphObject.click event handler must be a plain function that takes an InputEvent and the GraphObject as arguments: GraphObject | GoJS API
The CommandHandler.deleteSelection method is a function that is a method, so it expects to be called with this
bound to the CommandHandler object.
Clearly you cannot use a method where a plain function is called, because this
will not be bound.
click: function(e, button) {
e.diagram.commandHandler.deleteSelection();
}
This event handler also avoids the unnecessary closure on myDiagram
.
FYI, throughout the GoJS API all event handlers and other functional properties are plain functions that need not expect this
to be bound. That permits the free and easy use of arrow functions there and everywhere.
thanx got it