Can't Resize guest to span monitors

[Remowylliams]

Running Windows 7 amd64 Previously in version 4.3.12 and earlier, I could move a guest so it spanned monitors I have 4 of them. And the guest would resize the desktop.

Now since 4.3.14 (or) 4.3.16.. I can move a windowed guest so it crosses multiple monitors. But when I try to resize it. It snaps to one monitor window and fits itself inside the monitor still in windowed mode.

Since my monitors are pretty low res 1440x900 being able to expand my guests makes it much more useful.

I see this using Ubuntu 14.4 as a guest as well as Win XP as a guest.

I did upgrade everything to 4.3.18 and added the additions to the host and the guests.