I don't doubt what you're saying. But in my case, I installed poptray and it locked up solid every time I tried to fetch my mail. I don't really have the time to fool with something that didn't work from the jump.
It does look nice but it didn't work so time to move on. This is a Zimbra forum so troubleshooting poptray here would be inappropriate.
I came across a "class of service" item that looks promising:
COS->Preferences->enable toaster notification for new mail
Was not enabled by default. Clicked it on, saved and waiting to see if it works.
IMHO, this should be enabled by default so as to save noobs like me having to waste people's time troubleshooting non-existent problems
UPDATE: The above COS change didn't help. Still broken
