#1 Changing readOnly for range gives rendering errors

[Erik Arvidsson]

When changing the readOnly property for input type
range it changes its rendering from a slider to a
progress bar. Something broke over the weeks so now the
rendering is incorrect after changing this.

It also seems like the size grows by 1px every time a
change is done.

Steps to reproduce:

1. Open /test/verify.html
2. Click Read Only button and look at the slider.