I have noticed that occasionally when adding comments to a Test Run that is failed or needs retested, the comments text box does not keep up with my key strokes.
Every once and awhile a couple characters are missed.
I have experienced this in Google Chrome & IE8 (with compatibility mode on):
TestRail v220.127.116.1136 Beta
Google Chrome v18.104.22.168
Internet Explorer 8.0.6001.18828
I do have a DELL wireless keyboard and mouse, but I have not noticed the problem with anything else.