$PS1 does not render command-line prompt in color in a FreeBSD VM

[James E Keenan]

This question concerns display of colors in the command-line prompt on 
two different FreeBSD installations.

For a couple of months I have been using VirtualBox 5.1.2 to run 
FreeBSD-10.3 as a guest on an Ubuntu Linux 16.04 LTS host.  When working 
in this VM I have been trying to avoid Linuxisms so as to better learn 
how to work in a BSD environment.  One case:  I'm using Bourne shell 
rather than Bash as the shell for my own user.  In my .shrc file, I have 
this assignment for the spelling and color of my command-line prompt:

PS1="[^[[31m\W^[[0m] \$ "

... where in each of two cases the '^[' is the ESCAPE character \033. 
This produces a prompt which I can verbally describe as:

open-bracket in white; basename of pwd in red; close-bracket, space, 
dollar-sign, space in white

... which in the terminal looks like:

[jkeenan] $

where 'jkeenan' is in red and all the rest is in white.  So far so good.

Yesterday I installed FreeBSD-11 as a VM on the same Linux host -- only 
this time I switched to using VMWare to house the VM.  I brought over my 
.profile, .shrc, .vimrc, etc., files from the 10.3 VM to this new one. 
I expected them to Just Work.  However the terminal inside the VMWare 
console seems to be unable to digest the codes for color in the 
assignment to $PS1.  That value for $PS1 is rendering as:

[[31mjkeenan[0m] $

... all rendered in white; nothing in red.  The control sequences to 
change from white to red and back again are simply being literally 
displayed.

I should note that the VMWare console is perfectly capable of rendering 
different colors.  Vim gets nice colors in syntax highlighting for both 
sh and perl.

Does anyone have a clue as to why $PS1 DWIMs on FreeBSD-10.3 in 
VirtualBox while FreeBSD-11.0 does not in VMWare?

Thank you very much.
Jim Keenan