Tagging - Name autocompletion is case-sensitive
The tagging dialog's field for the tag's name (labelled Tag) helpfully offers a combo box, and autocompletion, which is very convenient. I was however confused when entering the common prefix of multiple tags offered no completion.
It turned out that the autocompletion is simply case-sensitive. As I was relying on completion, I entered "loi" with a lowercase "l", but existing tags were all named "Loi27...", so none matched.
The comparison with existing values should be case-insensitive.
This affects TortoiseHg 6.4.2 on Microsoft Windows 10.