Mouse click original event details

GoJS
1

Hi! I am using GoJS 1.7.9. I have a simple handler for event implemented like this:

myDiagram.addDiagramListener("BackgroundSingleClicked", function (e) {

});

Inside this handler I would like to check if shift or control buttons were pressed when click occurred. Normally in javascript I would use e.shiftKey property but in this case I cannot find this property in event object. Is there any way to get it?

Thank you,
K.S.

2 
  $(go.Diagram, . . .,
     { . . .,
       "BackgroundSingleClicked": function(de) {  // a DiagramEvent
         // diagram events are not necessarily due to an input event
         var ie = de.diagram.lastInput;  // the last InputEvent
         console.log(ie.shift + " " + ie.control);
       },
       . . .
    })