Alternatively, instead of assigning the region face to it as a defvar, you could use the same color values as region, but making semantic-idle-symbol-highlight-face a defface.

On Mon, Apr 8, 2013 at 1:20 PM, Barry OReilly <> wrote:
> If someone recommends a good light (white) background and dark  (black)
> background color to use, I can apply them.

I think subdued is best, so a possibility is:

For dark background:
  :background "#002220" :foreground "white"
For light background:
  :background "#ddfffd" :foreground "black"