Thunderbird links or attachments will open Firefox with single blank tab, but thinks it has two tabs open. However, if Firefox is already running it works ok
Not sure if this is a firefox issue or a Thunderbird one... But I believe it is a Firefox issue.
When clicking on an attachment or URL link in thunderbird, it will try to open firefox or a new tab in firefox, if it is already running. If the firefox was not open, it will open it, with a single blank tab with no content or URL listed. If I click the thunderbird attachment or link *AGAIN* it will opena new window with the same blank tab symptoms. Trying to close the firefox window it tells me that I have "2" tabs open, even though there is only one visible.
If firefox is already open with a working tab(s), clicking on the Thunderbird attachment or URL works like it should and it opens a new tab with URL shown and goes to web address or shows PDF file fine.
I do not believe that there is a virus/malware on the system. I'm running latest release.
This could be a problem with DDE.
Try to redo the default browser setting and temporarily set another browser as the default browser.