On the screen, it is not the computed background color that is seen
by a user. Since DOM elements can be transparent, the background
color might be one of the parent elements. This is why we need to
traverse the DOM tree to find the background color of the first
non-transparent parent element.
A more sophisticated solution would be to also use blending when
there is a non-fully transparent background color. I think that
might be a bit overkill for now.
See also spacetelescope/jdaviz#2264 (comment)
On the screen, it is not the computed background color that is seen by a user. Since DOM elements can be transparent, the background color might be one of the parent elements. This is why we need to traverse the DOM tree to find the background color of the first non-transparent parent element.
A more sophisticated solution would be to also use blending when there is a non-fully transparent background color. I think that might be a bit overkill for now.
See also spacetelescope/jdaviz#2264 (comment)
References
Code changes
User-facing changes
Backwards-incompatible changes