Comment 4 for bug 1390731

Hardcoded zooming is affecting badly to any other keyboard layout.

I.e: I'm using an latin american spanish (LA) keyboard.

1) If I set the system keyboard layout to US, the key combinations for zoom in and out, pressing the keys that would print the minus or the equal (`?` and `¿` in my keyboard) works.
2) If I set the system keyboard layout to LA, then that combination on point 1, doesn't work (super and ? or super and ¿).
3) If I set the system keyboard layout to LA, then the neither combination work: super shift 0 (`shift 0` is `=`) or super minus.

In conclusion, we can use the magnifier onlyif we change the layout to US.