mxConstraintHandler.prototype.getCellForEvent=function(a,b){var c=a.getCell();null!=c||null==b||a.getGraphX()==b.x&&a.getGraphY()==b.y||(c=this.graph.getCellAt(b.x,b.y));null==c||this.graph.isCellConnectable(c)||(a=this.graph.getModel().getParent(c),this.graph.getModel().isVertex(a)&&this.graph.isCellConnectable(a)&&(c=a));return this.graph.isCellLocked(c)?null:c};