To whom it may concern,
We've encountered a problem with Zimbra's webmail client. We are presently using the licensed version of ZCS 5.0.6 We found this problem to occur for all of our users on IE5, IE6, IE7, under a specific configuration while in 'Standard' mode. When creating a new message, a user can enter a 'To' address, 'Subject, etc. However, when a user attempts to focus (click-on) the email body text area, the cursor briefly flashes on the textarea and then doesn't allow any typing in that field. If you have a signature, use the 'Advanced Mode' (AJAX), check the 'As HTML' radio button (as found under Preferences->Compose tab), or are replying to an existing email -- you avoid the problem altogether. In other words, when some text already exists in the email body's textarea (or you are using a different textarea altogether, as with the HTML toolbar) you can type in the textarea with no problem. However, with a blank textarea, the email body's text field in unfocusable (i.e. disabled).
Talking to the individual responsible for managing our email, we believe the following thread closely matches the error we found with IE.
Compose new mail on webclient using html format
I'd also like to point that we've used Zimbra for a couple of months now, and despite the present issue, find Zimbra to be an excellent product.