osx - WKWebView strange behaviour when opening target="_blank" links on OS X -

i developing os x wrapper around popular web application, using wkwebview. however, when try open link app, strange behaviour:

• tap on link (the link has target="_blank")
• webview:createwebviewwithconfiguration:fornavigationaction:windowfeatures: called
• trying extract url navigationaction parameter in delegate method above empty url
• webview:runjavascriptalertpanelwithmessage:initiatedbyframe:completionhandler: method called following message parameter: "grrr! popup blocker may preventing application opening page. if have popup blocker, try disabling open window."

has experienced similar? idea doing fancy javascript track clicks , blocking normal link behaviour.