I just started up thunderbird 115.2.2 under Mageia 9 and there is no unified tool bar, which I find very convenient. I cannot find any setting to bring it back. Any help would be appreciated.
I had this same issue, looks like it's a weird bug. If you go to tools>account and scroll to the bottom under indexing. Unchecked and then re-check enable global search and indexer.
Thank you. That helped