I put WebView on DetailViewController (From template MasterViewController) and set constraints like below picture. But when navigate to every url, it has a black bar on top and it disappear when scroll down. How can I remove it?

**WebView**

[![WebView have black space bar](https://i.stack.imgur.com/sGMbZ.png)](https://i.stack.imgur.com/sGMbZ.png)

[![When set WebView background = clear color](https://i.stack.imgur.com/OSNc5.png)](https://i.stack.imgur.com/OSNc5.png)

**Constraints set**

[![Constraints](https://i.stack.imgur.com/ogAAp.png)](https://i.stack.imgur.com/ogAAp.png)