To better help you, please post here a screenshot showing us what you are seeing. See: How do I create a screenshot of my problem?

Also, I don't understand what you mean by "the new tab feature", so please post a screenshot of that also.

Hi Bruce, Under Tools>Options, there is a new capability to "Edit events and tasks in a tab instead of in a dialog window." If this is unchecked, so that events and tasks should be edited/configured in a pop-up (not in a tab), the pop-up window is blank. If I select this check box, new/edit calendar events and tasks show up in a tab, with the form to fill out the event/task. See attached screen shots.

Some folks internal in my company have stated that this new version of Thunderbird is not compatible with the Beehive addon we use, and that is causing the blank popup windows.

Can you confirm this and do you know if Mozilla is aware and can take a look?

Thanks, Eric

Ah. That option to "Edit events and tasks in a tab instead of in a dialog window" is indeed new, and I haven't noticed it before.

It is simple enough to determine if that add-on is causing the problem or not. Disable it, then restart Thunderbird. If the problem is gone, then you know it is that add-on.

If any add-on causes a problem, it is up to the author of the add-on to fix it, not the developers of Thunderbird.

Hi Bruce, Disabling the add-on allowed event and task pop-ups to work correctly. Since I need the addon, I'll use the "tab" feature for now.

Thanks much, Eric