I think the X button is most similar to the codeblock toolbar, but there are some style differences and I don't know why it's different. The codeblock toolbar has a button inside a box with a border with some padding, but the X button has no padding and seems larger?

Also, I think the X button and response toolbars should be visible when the row is focused, they way the X button used to be, otherwise they are impossible to navigate to with keyboard only. See how the codeblock toolbar sticks when focus is in the codeblock.