Symptoms

When trying to add text in email body using K2 Designer "Send Email" rule, after a few rows (more than 20 I believe) it doesn't accept any more text. It doesn't give any error but simply does not accept any input.
 

Diagnoses

We reproduced this on a 4.6.9 machine with IE8, 9 and 10.
 

Resolution

We have linked this issue to a TFS item, but the workaround here is to either use a different web browser, or to clear your browser's cache.

You can also use K2 Studio or Visual Studio to create a workflow that will kick off when a button is clicked in a Form for example that will then send an email. The email event in K2 Studio is much more robust than the web based email event in K2 Desginer.