I noticed for a while now that my thunderbird client is not receiving the mails "immediately" anymore, but has to regularly synchronize my IMAP folders with googlemail.
I am also using Trillian Instant Messenger on the same computer, which is configured to notify me of new emails in my googlemail account. This is also the only way I know that thunderbird is not receiving the PUSH mails, since I receive notifications via Trillian, while Thunderbird does not show the mails yet.
Now, my suspicion is that PUSH mails are only sent to one client per IP. Is this true? Is there something else involved I am not away of? I looked through the help for Thunderbird but as far as I could find, it will always receive PUSH mails without special options. Maybe I overlooked something.