mxDragSource.prototype.dragEnter=function(a,b){a.isMouseDown=!0;a.isMouseTrigger=mxEvent.isMouseEvent(b);this.previewElement=this.createPreviewElement(a);null!=this.previewElement&&this.checkEventSource&&mxClient.IS_SVG&&(this.previewElement.style.pointerEvents="none");this.isGuidesEnabled()&&null!=this.previewElement&&(this.currentGuide=new mxGuide(a,a.graphHandler.getGuideStates()));this.highlightDropTargets&&(this.currentHighlight=new mxCellHighlight(a,mxConstants.DROP_TARGET_COLOR));a.addListener(mxEvent.FIRE_MOUSE_EVENT,