How to customize the color of the symbol inserted in the "glasses mode" in emacs? I have not found the option for this. Can anyone suggest anything?
There's no option to set the face for the inserted separator (and from a brief study of the docs for emacs overlays, I don't think it's simple to add).
You can customize the face used for the capital letters that glasses-mode splits on; it's called glasses-face.
You can reset glasses-separator either by hand or in your .emacs file to change the symbol. My elisp is rusty, but I think
(setq glasses-separator "~")
does that. At this point we have not changed the type face at all.
I think you may have to hack the mode (glasses.el) to accomplish this.
(defers to Allen's better reading of the question...)
The easiest way to see the customisations available for glasses-mode is to enter:
M-x customize-group
and then enter glasses at the Customize group (default emacs): prompt.
However, you will need to set up a custom.el file first.