I assume it is the date zimlet that causes popups to appear when you mouse over dates in the calendar and in emails. Anyway, it seems to be a bit hit and miss, sometimes you get a list of appointments on that day, sometimes nothing. When you go back over a date in the small calendar (bottom left of the page) it might appear. It seems to be when you move directly to the next date is fails, if you go "up and over" passing over a few other dates then it displays fine.
In email I sometimes get "no appointments" when there definitely are, when I re-open the same email then the appointments show.
Of most concern though are the British date formats, in emails this is what happens;
08/01/2008 displays Friday, August 1, 2008 (Not it Britain it ain't)
25/01/2008 displays Tuesday January 1 2008 ??
1/22/2008 displays Tuesday January 2 2008 (That's invalid in the UK)
I was showing this to a colleague today and you could see how this little thing overshadowed all the other great things Zimbra does. It might have been better to disable the feature rather that it be a focus for something going wrong but the potential of this zimlet is great. My preferences are set to English UK, how can I get Zimbra to work with British format dates and is there anyway to get the mouse over to be a bit more reliable?