video bleeds through somewhat between sessions

[Mikus Grinbergs]

> It is the video chip's feature that it can display a video overlay over
> the RGB bitmap. The pixels where the overlay can be seen is defined by a
> colorkey (what was 0xFF00FF in the example), or the alpha component of
> the display RGB bitmap (not used on the XO since the change 16 bit
> bitmaps). What you are seeing that the X server does not disable the
> video overlay while switching programs. It can be an error or just some
> braindamaged X stuff. Either way, it has nothing to do with bitmap
> operations.

Then I believe there *was* something wrong:  When I was looking at 
the "character-based" Terminal screen, there should not have been a 
'video overlay' interacting with what was being shown to me.

When I am looking at the (full-screen) video output, if what I see 
involves a 'video overlay' -- that's fine with me.  But when I 
"switch away" from the 'session' displaying the video output, I 
don't want "interference" to what I'm currently looking at (whether 
that interference comes from a 'video overlay', or from whatever).


--------

Both persons who have answered me have talked about "how things from 
the video frame can be seen".  But I was not looking at video - I 
was looking at TEXT.  If I understand correctly what has been told 
me here, neither the 'black' of the text characters themselves, nor 
the 'white' of the background for the text, should have _allowed_ 
"things from the video frame to be seen".  I definitely did not see 
any color.  What I did see was that some parts of the 'black' text 
characters changed briefly to _less_ 'black' (they went black <--> 
gray <--> black) depending on where on *its* screen the ongoing 
video 'session' WOULD HAVE depicted "bright" or "dark" areas.


mikus