Error on Mouse Drag

[neurofuzzy]

I recently upgraded from PIXI 1.5.4 to 2.2 and I am getting this error when I drag the mouse on the canvas:

 

Uncaught TypeError: Cannot read property 'length' of undefined  PIXI.InteractionManager.collectInteractiveSprite	  PIXI.InteractionManager.collectInteractiveSprite	  PIXI.InteractionManager.rebuildInteractiveGraph	  PIXI.InteractionManager.onMouseMove	

It appears to be PIXI.InteractionManager.prototype.collectInteractiveSprite hitting a child node with no children array.

            if (child.children.length > 0)            {                this.collectInteractiveSprite(child, iParent);            }

Any clues as to what is going on? This problem also occurs in PIXI 1.6.0

 

[neurofuzzy]

I think I solved this. I was adding a PIXI.DisplayObject to a PIXI.DisplayObjectContainer on the stage. I was only using it as a reference point (origin), but it appears you can no longer add a DisplayObject, it must be at least a DisplayObjectContainer.