"hidpi Displays Support" Has Intermittent Error

I seem to be having an intermittent error when I have “HiDPI displays support” active. It may happen more often than I think, but I have repeated it multiple times using Firefox 28/29. For some reason if I have the HiDPI turned on and I add some items to the shopping cart, then click on the “view cart” the product ends up NOT really being added to the shopping cart. Then if I turn off the HiDPI and try to add it to the shopping cart it works fine. This does not always happen when HiDPI is turned on. Sometimes I can add 2 or 3 more items before I get the error of one not being added to the cart. But if I turn off the HiDPI when I add something to the cart, it always shows up in the cart. Seems kind of strange.

So here is what I am wondering:

  1. Is there really any reason to have the HiDPI turned on?
  2. Has anyone else found this same error?
  3. Does anyone use the HiDPI in version 4.1.?

I was wondering, does anyone turn on the HiDPI add-on at all?