While typing email the font size just changes larger and smaller

[WHYone]

I cannot type an email without the font changing to much larger size half way through the message. What is the cause of this?

[hracer]

I tested with my email account and I am not getting the same results as you are. What browser(Firefox, Chrome etc...) are you using? Have you made sure all your software and any browser plug-ins are up to date?