Thunderbird open multiple copies

[ineuw]

How can I prevent Thunderbird (currently using v31.3.0) from opening more than one copy. When Thunderbird opens a second copy, it also opens the email preview, which is an indication (for me) that there are two copies running.

[DanRaisch]

What are you doing when Thunderbird seems to launch a second instance? Can you post a screenshot of what you are seeing? http://kb.mozillazine.org/Posting_a_scr ... _the_forum

[ineuw]

Hi Dan, I couldn't repeat it now, but it did happen before on several occasions. The next time it happens I will remember to take a snapshot and return to this post. Thanks

[Diane Vigil]

I'd had that happen as well.

I duplicated it just now: I have Thunderbird installed along with the Lightning Calendar extension. Normally, I just have TB open, with the Lightning "Today Pane" sidebar displayed on the right side of the TB window.

To open the full Lightning calendar, I click the Lightning icon (little square icon near the top right of TB), and I now have two tabs -- TB in one and the full Lightning calendar in the other (and the Today Pane displaying in both tabs). Good enough.

If I then grab and drag the calendar tab (inadvertently/stuff happens), it will open a second instance of TB with the Lightning tab (but the Lightning tab is now not open in the original instance). Kind of like an "open new window" in Firefox.

Interestingly, if I have TB open, the Lightning tab open, and double-click an email to open it in a new tab, and drag that new email tab, I get a second instance of TB with the email tab (no Lightning tab).

This does not happen if I drag the TB tab.

[JWT]

I know this is fairly old and it is still happening (52.8.0 (64-bit) from Debian Testing). I click on the Calendar tab and it opens a second instance of Thunderbird.