It has not reproduce on my environment so the image was taken by removing all elements in the toolbar. It may be a little bit different from the actual case.
I have also experienced that issue while I developed Tag Toolbar v1.0.0, which was the reason of delay of Thunderbird 68 compatible Tag Toolbar.
It did not occur by changing the way of XUL overlay. So I thought it was resolved.
So far, the followings are the common in the bug reports:
- QuickFolders add-on is installed
- It works fine at the first time but it does not after restart of Thunderbird
As described the top of the post, I have not been able to reproduce the issue yet. However, by considering the situation, I doubt cache mechanisms of Thunderbird.
So, I implemented an experimental option to disable the cache in Toolbar 1.0.1b4.
Can you try it if you have the problem?
It may make start of Thunderbird slower. In case the option arises a problem on your environment, it can be disabled by the Tag Toolbar option. Uncheck the "Disable XUL cache mechanisms of Thunderbird".
Technically, it configures as follows:
- execute nsIXULRuntime.invalidateCachesOnRestart()
- set "nglayout.debug.disable_xul_cache" preference to true
