I send a lot of HTML emails. The problem with GMail is, if there are more than one emails with the same subject, it hides some similar content and shows a "..." to show the "trimmed content". This screws up with my formatting.
If changing the subject is not an option, is there is any way to avoid this behaviour?
Edit: I should clarify that I programmatically send emails using Amazon SES from a php script. That is why I posted the question in Stack Overflow.
I've just encountered this problem myself, and from my investigations it seems that GMail does indeed trim the content if it is similar to the preceding emails.
My solution is simply to insert the current time stamp at the end of every email:
[15:02:21 29/01/2013] End of message.