ContextMenuTool.showContextMenu:obj value is not an instance of GraphObject: undefined

GoJS
1

I have defined a context menu for my diagram with the following function:

SeatingMapGraphicsRef.contextMenu =
  GO(go.Adornment, "Vertical",
 // no binding, always visible button:
 GO("ContextMenuButton",
 GO(go.TextBlock, "Hold Seats"),
 { click: function(e, obj) {
  holdSeatsInDragSelect();
  } }),
 GO("ContextMenuButton",
 GO(go.TextBlock, "Select Seats"),
{ click: function(e, obj) {
 } }),
 GO("ContextMenuButton",
GO(go.TextBlock, "Lock Seats"),
{ click: function(e, obj) {
} }),
GO("ContextMenuButton",
GO(go.TextBlock, "Cancel"),
{ click: function(e, obj) {
  var diagram = e.diagram;
            diagram.hideContextMenu();
} })
);

where SeatingMapGraphicsRef is a reference to my GOJS diagram.

After calling defineDiagramContextMenu (which simply executes the above contextMenu definition) ,
I call the showContextMenu tool to programmatically display the context menu as opposed to doing the default command.

Here is the line I use to show the context menu

SeatingMapGraphicsRef.toolManager.contextMenuTool.showContextMenu(SeatingMapGraphicsRef.contextMenu);

This gives me the following error:

ContextMenuTool.showContextMenu:obj value is not an instance of GraphObject: undefined

Does anybody understand how it is the case that the contextMenu I created in my function did not create a GraphObject ?

2

So I misread the documentation. showContextMenu takes in both an Adornment and a GraphObject which in the case of diagram is null. Hence I should have written.

SeatingMapGraphicsRef.toolManager.contextMenuTool.showContextMenu(SeatingMapGraphicsRef.contextMenu, null);