ffClone = function (elem) {
  if (!isGecko()) { return elem }
  const clone = elem.cloneNode(true)
  elem.before(clone)
  elem.remove()
  svgCanvas.selectorManager.releaseSelector(elem)
  svgCanvas.setSelectedElements(0, clone)
  svgCanvas.selectorManager.requestSelector(clone).showGrips(true)
  return clone
}
Hack for Firefox bugs where text element features aren't updated or get
messed up. See issue 136 and issue 137.
This function clones the element and re-selects it.
@function module:svgcanvas~ffClone
@todo Test for this bug on load and add it to "support" object instead of
browser sniffing
@param {Element} elem - The (text) DOM element to clone
@returns {Element} Cloned element