Open an e-mail referring to imap://mail link (Mac)

[G548]

Hi,
I use thunderbird on Mac OS X. When I drag and drop a message to another window the message is referred to as imap://mail@<mailaddress>:993/fetch<...>INBOX<...>

I would like to use this link to open the e-mail later, ideally by just clicking on the link and a new window would open with the message. The only way to use the link is by changing to the directory Applications/Thunderbird.app/Contents/MacOS and calling thunderbird in a terminal window like this

./thunderbird -mail imap://mail@<mailaddress>:993/fetch<...>INBOX<...>

Then, a message appears that thunderbird is already running and that it is not possible to run two copies of thunderbird.

Is there a way to use the link directly from the main thunderbird window or with drag&drop of the link to some location in the main thunderbird window?