treeview.view:selected:focus {
    border: 1px dotted @border_color;
}

treeview header button {
    padding: 0.1em 0.7em;
    border-radius: 0;
    border-width: 0;
    border-bottom-width: 1px;
}
treeview header button:not(:last-child) {
    border-right-width: 1px;
}