[FIX] avoid duplicate buttons
[FIX] avoid duplicate buttons

jenswellmeyer/cordova-plugin-inappbrowser-fork,jenswellmeyer/cordova-plugin-inappbrowser-fork,jenswellmeyer/cordova-plugin-inappbrowser-fork,jenswellmeyer/cordova-plugin-inappbrowser-fork,jenswellmeyer/cordova-plugin-inappbrowser-fork