.bashrc

if [ -z "$WP" ]; then
   # $WP is empty... you are not in a chroot workspace
   export PS1="\[\033[0;31m\]"$PS1"\[\033[0m\]"
else
   # $WP contains the name of the project you're currently in
   export PS1="\[\033[0;37m\]"$WP": "$PS1"\[\033[0m\]"
fi

Non printable characters (like \033[0;37m) must be wrapped in \[ blah blah blah \].

If not, bash doesn't know how many characters long the prompt is and when you type long commands they won't wrap properly.

If your terminal has a light background, consider different colors. I have PS1="[\033[0;42m]"$WP": "$PS1"[\033[0m]" because my background is white and I couldn't read gray against white.