graph edges wont move to right position when toggle legend

### Version
5.0.2

### Reproduction link
[https://jsfiddle.net/w3fnsaLz/6/](https://jsfiddle.net/w3fnsaLz/6/)

### Steps to reproduce
toggle the legend to hide

toggle back

watch the edges and node position

if not reproduced

toggle the legend to hide again

and then toggle back

### What is expected?
the edges and nodes layout updated

### What is actually happening?
it is updated, but not in the right postion

---
if i change the source code in GraphView.js
```js
GraphView.prototype._startForceLayoutIteration = function (forceLayout, layoutAnimation) {
var self = this;

(function step() {
forceLayout.step(function (stopped) {
self.updateLayout(self._model);
(self._layouting = !stopped) && (layoutAnimation ? self._layoutTimeout = setTimeout(step, 16) : step());
(stopped) && (self._layoutTimeout = setTimeout(step, 16));
});
})();
};
```
it will jump to the right position, but i dont think its the best solution.