I’ve had a really annoying problem where the cursor in Gmail disappears completely when composing mails. Being used to have a visual hint of where the next character is supposed to be placed, I was pleased to find a blog post [1] describing a workaround.
The short story of the workaround it is to disable the advanced attachment features in Gmail.
You can look at the blog post to find out when the problem occur, why it does and why the workaround helps:
I was having the same problems untill recently. Haven’t done anything. Now i know what to do when it happens again. Thanks!