I haven't read through this whole thread so someone may have already said the same thing. But I have found that whenever I am writing a reply, mid-writing my cursor will just disappear and my keyboard turns into it's simple functions. So I will be trying and it will dissappear while I continue to write and if I press the space bar it moves the page down and if I press backspace I go back a page, losing my writing. This may just be a problem with my computer, but I just thought I'd see if anyone else has the problem, or knows how to combat it.