According to Micro Focus, the .FullScreen method will not work with Edge ([https://admhelp.microfocus.com/uft/en/14.01/UFT_Help/Content/Addins_Guide/EdgeLims.htm?Highlight=edge#hp-minitoc-item-2][1]) However I have found that with the current Windows 10 Creator's Fall Update, it does work.
I have not found a way to reliably resize the Edge Browser, however, you can minimize and maximize it. See below code, using UI Automation. You will need to add the objects to the Object Repository.
Note that .Resize and .Move will not work.
SystemUtil.Run ''C:Program Files (x86)HPUnified Functional TestingbinWebDriverHost.exe'', ''https://the-internet.herokuapp.com/''
Browser(''The Internet'').FullScreen
wait(3)
UIAWindow(''The Internet ?- Microsoft'').Activate
wait(3)
UIAWindow(''The Internet ?- Microsoft'').Minimize
wait(3)
UIAWindow(''The Internet ?- Microsoft'').Maximize
wait(3)
msgbox (UIAWindow(''The Internet ?- Microsoft'').CanMove)
msgbox (UIAWindow(''The Internet ?- Microsoft'').CanResize)
If I find a way to get .Move or .Resize to work, I will update this post.
[1]: https://admhelp.microfocus.com/uft/en/14.01/UFT_Help/Content/Addins_Guide/EdgeLims.htm?Highlight=edge#hp-minitoc-item-2