2010/7/11 Eli Zaretskii <eliz@gnu.org>:
> So let's back up a bit and see if we have the whole picture:
>
>  . What happens in "emacs -Q" without evaluating
>
>     (set-foreground-color "black")
>     (set-background-color "white")
>
>   ?  Is the cursor visible?  Is it black?
>

It is blinking, visible and black.

>  . Which one of the above expressions triggers the problem when
>   evaluated?  Is the order of evaluating them important?
>

Assuming you meant (set-foreground-color "white") and
(set-background-color "black")...

Scenario 1:
1. I set the foreground to white, everything remains fine.
2. I set the background to black, the problem as originally described
happens, i.e. the cursor is invisible on default face text. I cannot
see anything blinking.

Scenario 2:
1. I set the background to black. The cursor *looks* invisible on
default text every other blink, but this is expected, since the text
is black on black background.
2. I set the foreground to white, the problem as originally described happens.

>  . When you set the background color of the `cursor' face, does the
>   problem happen only with the black color?  What about colors close
>   to black, like "gray1", "gray2", etc.? how about "gray40" or
>   "gray80"?
>

Assuming white foreground and black background...

I set the cursor color to #333333, which is nearly black but still
visible on black background. During the time period at which the
cursor is not visible (the first half of the blinking), everything
looks fine. When the cursor is visible (the other half of the
blinking), the text which is normally white (default face) appears
black. I can see the #333333 cursor behind the text. I have attached a
GIF screenshot of this.

-- 
Deniz Dogan