Desktop overlaps the screen

[Brian]

I've tried sending a request to the manufacturer's tech support
address, but I thought I would ask here as well, just in case somebody
has solved the problem.

I've just got a 32 inch Element (brand) TV from WalMart for use as a
monitor. The problem I'm having is that, irrespective of the
resolution to which I set the graphics card (I've tried four different
ones) the desktop slightly overlaps the visible area of the screen.
I've been all the way through the TV menus, multiple times, and can
find no setting like there used to be on the old CRT monitors to
shrink the picture down slightly. It's very annoying, because if I
have an application in full screen, the 'File' menu is JUST about
clickable (I can see the edge of the 'e') and the close button is
inaccessible.

I'm using Ubuntu 18.04 LTS and the version of XFCE distributed with
that, which means 4.12.

Any suggestions, folks? And that includes any ideas of a more relvant
mailing list on which to ask, if need be.

Thanks,

Brian.