Tab and WebView problem

It will become clear as you read that I have very little experience programming please excuse me for an elementary question. I have on the storyboard the template for a tab based app. which has two view controllers both of which have a web view on them and both seem to be working fine. As I needed a third tab I dragged a view controller onto the storyboard and linked it to the tab bar controller, I also created a "thirdViewContoller.swift" file which was copied from one of the other two which was in the template. Ran the app and everything works fine. I now drag a UiWebView onto the third view controller and unlike the other two when I try to control drag the webView to the code it will not link up. What am I missing. Many thanks for any help.