Thunderbird will not run scripts so anything based on a script delivering content will fail in Thunderbird. It is this fact that makes opening emails "safer" than most mail products because you can't get a drive by infection from some web site just by opening an email. It does however have it's downsides, like Google maps directions just don't work as expected because they rely on scripts. I am guessing that your "blank" space is driven by a script. You could post the content to Mozilla's pastebin with a 28 day expiry and someone might have time to look at it to determine if it is a script issue. Instructions for pastebin as follows. # Go to https://pastebin.mozilla.org/, paste the copied content by right clicking in the large text area, select paste from the menu, change the retention period to expire in 28 days, use the '''Paste Snippet''' button to create a page containing your info, then copy the resulting URL (address) of the page created. # Open a reply to this post, and paste the URL to your troubleshooting information you just copied.