Unable to resize guest window size in Windows 10

I am using VMware Workstation 15 Player (free edition), and have Ubuntu 18 64 bit as a guest, on Windows 10 machine.

It runs fine, but for some reason, the guest window size is fixed. When I drag the bottom corner to increase the size, and it just "snaps back" to the default size.

I'm sure I ran it a couple of months ago, and I could resize to whatever size I wanted without issue.

Any idea how to resolve the issue?

Thanks so much,

Lee