selction:created event never triggers

[salman-git]

Hi, I am using OpenseadragonFabricjsOverlay fabricCanvas over osd. I have hooked 'canvas-press' and 'canvas-release' events of viewer and other events of canvas like mouse:move, mouse:out, mouse:out and selection:created. all events are working correctly except selection:created. I have checked all my objects are selectable. What I think is that canvas-press and canvas-release is somehow blocking selection:created event.
why am I using viewer.addHandler('canvas-press'...) instead of canvas.on('mouse:down')? well, the canvas.on('mouse:down') is also not working.