If a user selects a Duotone icon, but assigns 0% alpha to both Color1 and Color2 to render the icon essentially invisible (because: reasons), note that this causes the selected icon to fade from view entirely in the Styles > Tile Overrides dialogue (underlined in red):
While it’s expected that the icon would normally be shown here in its styled form (‘Light’, etc.), this rare circumstance may require special treatment – even if that just means showing the icon name? – so the user can at least know which icon is in use.
Gonna call that one a bug and could add some code to fix it so that it will be shown with alpha fixed to no lower than 50% - BUT, there are still cases where if you selected black for both colors it will also be invisible, so not sure that’s sorted either.
Also, given the multiple ways you can render the icon to be hard to visually see, should I just fix the color and alpha to light and dark grey so you know it’s a duo-tone but the true colour is actually only shown when on a tile or in the icon chooser???
Yes, that last thing you said.
A change to simply show the same non-colored duo icon should enable it to be seen