How can I get rid of the border around the folder with selected+focus?

Thunderbird
#1

I have tried several things to get rid of the border around the selected folder when the app has focus, but none of them has worked:

#folderTree > treechildren::-moz-tree-row(selected, focus) {
border: none !important;
}
#folderTree > treechildren::-moz-tree-cell(selected, focus) {
border: none !important;
}
#folderTree > treechildren::-moz-tree-cell-text(selected, focus) {
border: none !important;
}

If I change “none” to “2px solid [color]” where [color] is a different one of red, green, or blue, each of these borders appears and STILL the border I am trying to get rid of is there.

I suspect there is another element outside the row that has this border I’m trying to get rid of, but I don’t know what it is or how to select it in my userChrome.css

Any ideas?

#2

I assume that you’re seeing a blue border with Thunderbird 102. If so, then try:

#folderTree treechildren::-moz-tree-row(selected) {
outline: none !important;
}

#3

Absolutely. Thank you.

Outline is a new one on me. I still have much to learn about CSS.