Inside a popup I have a button whose destination is an externalURL.
When I click the button the URL I get the page I want, however the page appears completely inside the initial popup. Since the popup has a very small size and the page obtained is much larger, I tried to open the url in a new window, for that I used the extended proprerties target = "_blank", but without success.

Any ideas or suggestions

Hi ,

Your popup should notify the parent and then the parent will make the navigation. 

The popup is a iframe that contains a webview so when you make it navigate the popup is like your "Main Window".

Good Luck.