xfce set a terminal preference color to transparent

Within the XFCE Terminal Preferences is a color tab for various items such as Cursor color, text selection and bold selection. They are initially a checkered value which suggests transparent. Once you’ve changed one, accidentally or not, I don’t see how to get it back to the checkered value.

I have right clicked in the terminal area then selected preferences then selected colors then selected one, say Bold Selection Color. I am now presented with “pick a color” where I can choose an existing color or, custom. At no point here nor within custom can I select transparent (or that checkered pattern).

I’m not what the checkered pattern means, perhaps transparent or maybe default, although if default I don’t know how to find what that default value is. I am transitioning from Xubuntu 24.04 to 26.04. I find my question is not specific to a release of Xubuntu since for this specific thing, it applies to 24.04 and 26.04. If I remember correctly I saw it back in the day of 22.04 as well.