I knew where this function was before the change in the format of block settings. I've found a few threads here with directions on how to do it, but they all seem to be out of date now.
Where has this function moved? I'm revising a course and need to change the color and contrast of all markers for that image all at once.
To fully redesign your markers, I have some documentation here- https://theme-360.com/theme-component/labeled-graphic-states/
In addition to changing the marker color, I also provide the css for unlimited numbering. I also have a design file you can download and design your own marker- to test with your own images.
Finally found it!
It's under the Format (triangle icon) button for the content block, not the Design menu or the Content menu.
