A friend of mine noticed that, if your Workboard has a background color, the contrast of the menu is not enough (opacity 0.9):

Some of you may not have any problem with that, but some other users may have some difficulties in distinguishing the text of the menu, and the text of the below Column.

Maybe a good compromise is opacity 0.95:

This is the current CSS rule:

.phui-workboard-color .phuix-dropdown-menu {
  background-color: rgba({$alphawhite},.9);

 }

https://we.phorge.it/source/phorge/browse/master/webroot/rsrc/css/phui/workboards/phui-workboard-color.css

It seems this opacity change was introduced in 2016:

https://secure.phabricator.com/D15269

https://secure.phabricator.com/rPc1f57605ab341b04417a0b28a2db9c92385a8a73