advance 1 variation, then "change" to grayscale mode again.
repeat
Unexpected result: background is gray, but shapes are still colored. Curiously, unexpected result doesn't happen first time, only second and subsequent time that steps are followed.
Doesn't happen with color override mode.
On further investigation, it appears that some objects changed grayscale, and others don't. Maybe sometimes they all don't. And the background doesn't.
Doesn't happen with color override mode.
On further investigation, it appears that some objects changed grayscale, and others don't. Maybe sometimes they all don't. And the background doesn't.