Rated 4 out of 5 stars

I've been missing this button. Works well in light mode. Button icon barely visible in dark mode.

I used the following CSS in my userChrome.css to fix this:

toolbarbutton#platinummyr_replyallbutton_addons_thunderbird_net-messageDisplayAction-toolbarbutton {
& > stack.toolbarbutton-badge-stack {
& > image.toolbarbutton-icon {
list-style-image: url("chrome://messenger/skin/icons/new/compact/reply-all.svg") !important
}
}
}

This user has a previous review of this add-on.

Thanks for the feedback. I'll try to see about fixing the UI to work with dark mode.