skritter being a bit slow in firefox the last two days i tried two other browsers just now and here is what I found out:
using skritter in chrome is ok but it feels a bit "shaky" - meaning the writing window is a bit flickering.
the second alternative browser i tried was safari and this was by far the worst result. same flickering feeling and the cursor sometimes appeared as arrow and sometimes as black dot as it should be.
so after this quick trial excursion i return happily to firefox. in firefox skritter feels stable and good.