elements () {
    const elems = []
    let cmd = this.stack.length
    while (cmd--) {
      if (!this.stack[cmd]) continue
      const thisElems = this.stack[cmd].elements()
      let elem = thisElems.length
      while (elem--) {
        if (!elems.includes(thisElems[elem])) { elems.push(thisElems[elem]) }
      }
    }
    return elems
  }
Iterate through all our subcommands.
@returns {Element[]} All the elements we are changing